diff --git a/docs/gateway/configuration.md b/docs/gateway/configuration.md
index 46ba7af67b..bfce441c30 100644
--- a/docs/gateway/configuration.md
+++ b/docs/gateway/configuration.md
@@ -126,6 +126,7 @@ When validation fails:
 
     - `agents.defaults.models` defines the model catalog and acts as the allowlist for `/model`.
     - Model refs use `provider/model` format (e.g. `anthropic/claude-opus-4-6`).
+    - `agents.defaults.imageMaxDimensionPx` controls transcript/tool image downscaling (default `1200`).
     - See [Models CLI](/concepts/models) for switching models in chat and [Model Failover](/concepts/model-failover) for auth rotation and fallback behavior.
     - For custom/self-hosted providers, see [Custom providers](/gateway/configuration-reference#custom-providers-and-base-urls) in the reference.
 
diff --git a/docs/reference/transcript-hygiene.md b/docs/reference/transcript-hygiene.md
index 5155f2f297..95e029aec7 100644
--- a/docs/reference/transcript-hygiene.md
+++ b/docs/reference/transcript-hygiene.md
@@ -57,6 +57,7 @@ Implementation:
 
 - `sanitizeSessionMessagesImages` in `src/agents/pi-embedded-helpers/images.ts`
 - `sanitizeContentBlocksImages` in `src/agents/tool-images.ts`
+- Max image side is configurable via `agents.defaults.imageMaxDimensionPx` (default: `1200`).
 
 ---
 
diff --git a/src/agents/image-sanitization.test.ts b/src/agents/image-sanitization.test.ts
new file mode 100644
index 0000000000..f6eb34e4b2
--- /dev/null
+++ b/src/agents/image-sanitization.test.ts
@@ -0,0 +1,20 @@
+import { describe, expect, it } from "vitest";
+import type { OpenClawConfig } from "../config/config.js";
+import { resolveImageSanitizationLimits } from "./image-sanitization.js";
+
+describe("image sanitization config", () => {
+  it("defaults when no config value exists", () => {
+    expect(resolveImageSanitizationLimits(undefined)).toEqual({});
+    expect(
+      resolveImageSanitizationLimits({ agents: { defaults: {} } } as unknown as OpenClawConfig),
+    ).toEqual({});
+  });
+
+  it("reads and normalizes agents.defaults.imageMaxDimensionPx", () => {
+    expect(
+      resolveImageSanitizationLimits({
+        agents: { defaults: { imageMaxDimensionPx: 1600.9 } },
+      } as unknown as OpenClawConfig),
+    ).toEqual({ maxDimensionPx: 1600 });
+  });
+});
diff --git a/src/agents/image-sanitization.ts b/src/agents/image-sanitization.ts
new file mode 100644
index 0000000000..0c40972671
--- /dev/null
+++ b/src/agents/image-sanitization.ts
@@ -0,0 +1,17 @@
+import type { OpenClawConfig } from "../config/config.js";
+
+export type ImageSanitizationLimits = {
+  maxDimensionPx?: number;
+  maxBytes?: number;
+};
+
+export const DEFAULT_IMAGE_MAX_DIMENSION_PX = 1200;
+export const DEFAULT_IMAGE_MAX_BYTES = 5 * 1024 * 1024;
+
+export function resolveImageSanitizationLimits(cfg?: OpenClawConfig): ImageSanitizationLimits {
+  const configured = cfg?.agents?.defaults?.imageMaxDimensionPx;
+  if (typeof configured !== "number" || !Number.isFinite(configured)) {
+    return {};
+  }
+  return { maxDimensionPx: Math.max(1, Math.floor(configured)) };
+}
diff --git a/src/agents/openclaw-tools.ts b/src/agents/openclaw-tools.ts
index 83590d3bf8..cad2b88d94 100644
--- a/src/agents/openclaw-tools.ts
+++ b/src/agents/openclaw-tools.ts
@@ -1,12 +1,12 @@
 import type { OpenClawConfig } from "../config/config.js";
-import { resolvePluginTools } from "../plugins/tools.js";
 import type { GatewayMessageChannel } from "../utils/message-channel.js";
-import { resolveSessionAgentId } from "./agent-scope.js";
 import type { SandboxFsBridge } from "./sandbox/fs-bridge.js";
+import type { AnyAgentTool } from "./tools/common.js";
+import { resolvePluginTools } from "../plugins/tools.js";
+import { resolveSessionAgentId } from "./agent-scope.js";
 import { createAgentsListTool } from "./tools/agents-list-tool.js";
 import { createBrowserTool } from "./tools/browser-tool.js";
 import { createCanvasTool } from "./tools/canvas-tool.js";
-import type { AnyAgentTool } from "./tools/common.js";
 import { createCronTool } from "./tools/cron-tool.js";
 import { createGatewayTool } from "./tools/gateway-tool.js";
 import { createImageTool } from "./tools/image-tool.js";
@@ -102,7 +102,7 @@ export function createOpenClawTools(options?: {
       sandboxBridgeUrl: options?.sandboxBrowserBridgeUrl,
       allowHostControl: options?.allowHostBrowserControl,
     }),
-    createCanvasTool(),
+    createCanvasTool({ config: options?.config }),
     createNodesTool({
       agentSessionKey: options?.agentSessionKey,
       config: options?.config,
diff --git a/src/agents/pi-embedded-helpers/images.ts b/src/agents/pi-embedded-helpers/images.ts
index 9162bb812b..c3b4d0a371 100644
--- a/src/agents/pi-embedded-helpers/images.ts
+++ b/src/agents/pi-embedded-helpers/images.ts
@@ -1,4 +1,5 @@
 import type { AgentMessage, AgentToolResult } from "@mariozechner/pi-agent-core";
+import type { ImageSanitizationLimits } from "../image-sanitization.js";
 import type { ToolCallIdMode } from "../tool-call-id.js";
 import { sanitizeToolCallIdsForCloudCodeAssist } from "../tool-call-id.js";
 import { sanitizeContentBlocksImages } from "../tool-images.js";
@@ -45,12 +46,16 @@ export async function sanitizeSessionMessagesImages(
       allowBase64Only?: boolean;
       includeCamelCase?: boolean;
     };
-  },
+  } & ImageSanitizationLimits,
 ): Promise<AgentMessage[]> {
   const sanitizeMode = options?.sanitizeMode ?? "full";
   const allowNonImageSanitization = sanitizeMode === "full";
+  const imageSanitization = {
+    maxDimensionPx: options?.maxDimensionPx,
+    maxBytes: options?.maxBytes,
+  };
   // We sanitize historical session messages because Anthropic can reject a request
-  // if the transcript contains oversized base64 images (see MAX_IMAGE_DIMENSION_PX).
+  // if the transcript contains oversized base64 images (default max side 1200px).
   const sanitizedIds =
     allowNonImageSanitization && options?.sanitizeToolCallIds
       ? sanitizeToolCallIdsForCloudCodeAssist(messages, options.toolCallIdMode)
@@ -69,6 +74,7 @@ export async function sanitizeSessionMessagesImages(
       const nextContent = (await sanitizeContentBlocksImages(
         content,
         label,
+        imageSanitization,
       )) as unknown as typeof toolMsg.content;
       out.push({ ...toolMsg, content: nextContent });
       continue;
@@ -81,6 +87,7 @@ export async function sanitizeSessionMessagesImages(
         const nextContent = (await sanitizeContentBlocksImages(
           content as unknown as ContentBlock[],
           label,
+          imageSanitization,
         )) as unknown as typeof userMsg.content;
         out.push({ ...userMsg, content: nextContent });
         continue;
@@ -95,6 +102,7 @@ export async function sanitizeSessionMessagesImages(
           const nextContent = (await sanitizeContentBlocksImages(
             content as unknown as ContentBlock[],
             label,
+            imageSanitization,
           )) as unknown as typeof assistantMsg.content;
           out.push({ ...assistantMsg, content: nextContent });
         } else {
@@ -108,6 +116,7 @@ export async function sanitizeSessionMessagesImages(
           const nextContent = (await sanitizeContentBlocksImages(
             content as unknown as ContentBlock[],
             label,
+            imageSanitization,
           )) as unknown as typeof assistantMsg.content;
           out.push({ ...assistantMsg, content: nextContent });
           continue;
@@ -129,6 +138,7 @@ export async function sanitizeSessionMessagesImages(
         const finalContent = (await sanitizeContentBlocksImages(
           filteredContent as unknown as ContentBlock[],
           label,
+          imageSanitization,
         )) as unknown as typeof assistantMsg.content;
         if (finalContent.length === 0) {
           continue;
diff --git a/src/agents/pi-embedded-runner/compact.ts b/src/agents/pi-embedded-runner/compact.ts
index 4197da59bf..94e48576e6 100644
--- a/src/agents/pi-embedded-runner/compact.ts
+++ b/src/agents/pi-embedded-runner/compact.ts
@@ -1,5 +1,3 @@
-import fs from "node:fs/promises";
-import os from "node:os";
 import type { AgentMessage } from "@mariozechner/pi-agent-core";
 import {
   createAgentSession,
@@ -7,10 +5,14 @@ import {
   SessionManager,
   SettingsManager,
 } from "@mariozechner/pi-coding-agent";
-import { resolveHeartbeatPrompt } from "../../auto-reply/heartbeat.js";
+import fs from "node:fs/promises";
+import os from "node:os";
 import type { ReasoningLevel, ThinkLevel } from "../../auto-reply/thinking.js";
-import { resolveChannelCapabilities } from "../../config/channel-capabilities.js";
 import type { OpenClawConfig } from "../../config/config.js";
+import type { ExecElevatedDefaults } from "../bash-tools.js";
+import type { EmbeddedPiCompactResult } from "./types.js";
+import { resolveHeartbeatPrompt } from "../../auto-reply/heartbeat.js";
+import { resolveChannelCapabilities } from "../../config/channel-capabilities.js";
 import { getMachineDisplayName } from "../../infra/machine-name.js";
 import { getGlobalHookRunner } from "../../plugins/hook-runner-global.js";
 import { type enqueueCommand, enqueueCommandInLane } from "../../process/command-queue.js";
@@ -24,7 +26,6 @@ import { normalizeMessageChannel } from "../../utils/message-channel.js";
 import { isReasoningTagProvider } from "../../utils/provider-utils.js";
 import { resolveOpenClawAgentDir } from "../agent-paths.js";
 import { resolveSessionAgentIds } from "../agent-scope.js";
-import type { ExecElevatedDefaults } from "../bash-tools.js";
 import { makeBootstrapWarn, resolveBootstrapContextForRun } from "../bootstrap-files.js";
 import { listChannelSupportedActions, resolveChannelMessageToolHints } from "../channel-tools.js";
 import { formatUserTime, resolveUserTimeFormat, resolveUserTimezone } from "../date-time.js";
@@ -81,7 +82,6 @@ import {
   createSystemPromptOverride,
 } from "./system-prompt.js";
 import { splitSdkTools } from "./tool-split.js";
-import type { EmbeddedPiCompactResult } from "./types.js";
 import { describeUnknownError, mapThinkingLevel } from "./utils.js";
 import { flushPendingToolResultsAfterIdle } from "./wait-for-idle-before-flush.js";
 
@@ -570,6 +570,7 @@ export async function compactEmbeddedPiSessionDirect(
           modelApi: model.api,
           modelId,
           provider,
+          config: params.config,
           sessionManager,
           sessionId: params.sessionId,
           policy: transcriptPolicy,
diff --git a/src/agents/pi-embedded-runner/google.ts b/src/agents/pi-embedded-runner/google.ts
index 6cd261e4f9..7c3767fbc1 100644
--- a/src/agents/pi-embedded-runner/google.ts
+++ b/src/agents/pi-embedded-runner/google.ts
@@ -1,12 +1,15 @@
-import { EventEmitter } from "node:events";
 import type { AgentMessage, AgentTool } from "@mariozechner/pi-agent-core";
 import type { SessionManager } from "@mariozechner/pi-coding-agent";
 import type { TSchema } from "@sinclair/typebox";
+import { EventEmitter } from "node:events";
+import type { OpenClawConfig } from "../../config/config.js";
+import type { TranscriptPolicy } from "../transcript-policy.js";
 import { registerUnhandledRejectionHandler } from "../../infra/unhandled-rejections.js";
 import {
   hasInterSessionUserProvenance,
   normalizeInputProvenance,
 } from "../../sessions/input-provenance.js";
+import { resolveImageSanitizationLimits } from "../image-sanitization.js";
 import {
   downgradeOpenAIReasoningBlocks,
   isCompactionFailureError,
@@ -20,7 +23,6 @@ import {
   stripToolResultDetails,
   sanitizeToolUseResultPairing,
 } from "../session-transcript-repair.js";
-import type { TranscriptPolicy } from "../transcript-policy.js";
 import { resolveTranscriptPolicy } from "../transcript-policy.js";
 import { log } from "./logger.js";
 import { describeUnknownError } from "./utils.js";
@@ -416,6 +418,7 @@ export async function sanitizeSessionHistory(params: {
   modelApi?: string | null;
   modelId?: string;
   provider?: string;
+  config?: OpenClawConfig;
   sessionManager: SessionManager;
   sessionId: string;
   policy?: TranscriptPolicy;
@@ -438,6 +441,7 @@ export async function sanitizeSessionHistory(params: {
       toolCallIdMode: policy.toolCallIdMode,
       preserveSignatures: policy.preserveSignatures,
       sanitizeThoughtSignatures: policy.sanitizeThoughtSignatures,
+      ...resolveImageSanitizationLimits(params.config),
     },
   );
   const sanitizedThinking = policy.normalizeAntigravityThinkingBlocks
diff --git a/src/agents/pi-embedded-runner/run/attempt.ts b/src/agents/pi-embedded-runner/run/attempt.ts
index 3c41489896..e9901636ca 100644
--- a/src/agents/pi-embedded-runner/run/attempt.ts
+++ b/src/agents/pi-embedded-runner/run/attempt.ts
@@ -1,9 +1,10 @@
-import fs from "node:fs/promises";
-import os from "node:os";
 import type { AgentMessage } from "@mariozechner/pi-agent-core";
 import type { ImageContent } from "@mariozechner/pi-ai";
 import { streamSimple } from "@mariozechner/pi-ai";
 import { createAgentSession, SessionManager, SettingsManager } from "@mariozechner/pi-coding-agent";
+import fs from "node:fs/promises";
+import os from "node:os";
+import type { EmbeddedRunAttemptParams, EmbeddedRunAttemptResult } from "./types.js";
 import { resolveHeartbeatPrompt } from "../../../auto-reply/heartbeat.js";
 import { resolveChannelCapabilities } from "../../../config/channel-capabilities.js";
 import { getMachineDisplayName } from "../../../infra/machine-name.js";
@@ -33,6 +34,7 @@ import {
 import { DEFAULT_CONTEXT_TOKENS } from "../../defaults.js";
 import { resolveOpenClawDocsPath } from "../../docs-path.js";
 import { isTimeoutError } from "../../failover-error.js";
+import { resolveImageSanitizationLimits } from "../../image-sanitization.js";
 import { resolveModelAuthMode } from "../../model-auth.js";
 import { resolveDefaultModelForAgent } from "../../model-selection.js";
 import { createOllamaStreamFn, OLLAMA_NATIVE_BASE_URL } from "../../ollama-stream.js";
@@ -105,7 +107,6 @@ import {
   shouldFlagCompactionTimeout,
 } from "./compaction-timeout.js";
 import { detectAndLoadPromptImages } from "./images.js";
-import type { EmbeddedRunAttemptParams, EmbeddedRunAttemptResult } from "./types.js";
 
 export function injectHistoryImagesIntoMessages(
   messages: AgentMessage[],
@@ -666,6 +667,7 @@ export async function runEmbeddedAttempt(
           modelApi: params.model.api,
           modelId: params.modelId,
           provider: params.provider,
+          config: params.config,
           sessionManager,
           sessionId: params.sessionId,
           policy: transcriptPolicy,
@@ -968,6 +970,7 @@ export async function runEmbeddedAttempt(
             existingImages: params.images,
             historyMessages: activeSession.messages,
             maxBytes: MAX_IMAGE_BYTES,
+            maxDimensionPx: resolveImageSanitizationLimits(params.config).maxDimensionPx,
             // Enforce sandbox path restrictions when sandbox is enabled
             sandbox:
               sandbox?.enabled && sandbox?.fsBridge
diff --git a/src/agents/pi-embedded-runner/run/images.ts b/src/agents/pi-embedded-runner/run/images.ts
index be6f8d0373..c328fd53f7 100644
--- a/src/agents/pi-embedded-runner/run/images.ts
+++ b/src/agents/pi-embedded-runner/run/images.ts
@@ -1,9 +1,10 @@
+import type { ImageContent } from "@mariozechner/pi-ai";
 import path from "node:path";
 import { fileURLToPath } from "node:url";
-import type { ImageContent } from "@mariozechner/pi-ai";
+import type { ImageSanitizationLimits } from "../../image-sanitization.js";
+import type { SandboxFsBridge } from "../../sandbox/fs-bridge.js";
 import { resolveUserPath } from "../../../utils.js";
 import { loadWebMedia } from "../../../web/media.js";
-import type { SandboxFsBridge } from "../../sandbox/fs-bridge.js";
 import { sanitizeImageBlocks } from "../../tool-images.js";
 import { log } from "../logger.js";
 
@@ -48,8 +49,13 @@ function isImageExtension(filePath: string): boolean {
 async function sanitizeImagesWithLog(
   images: ImageContent[],
   label: string,
+  imageSanitization?: ImageSanitizationLimits,
 ): Promise<ImageContent[]> {
-  const { images: sanitized, dropped } = await sanitizeImageBlocks(images, label);
+  const { images: sanitized, dropped } = await sanitizeImageBlocks(
+    images,
+    label,
+    imageSanitization,
+  );
   if (dropped > 0) {
     log.warn(`Native image: dropped ${dropped} image(s) after sanitization (${label}).`);
   }
@@ -354,6 +360,7 @@ export async function detectAndLoadPromptImages(params: {
   existingImages?: ImageContent[];
   historyMessages?: unknown[];
   maxBytes?: number;
+  maxDimensionPx?: number;
   sandbox?: { root: string; bridge: SandboxFsBridge };
 }): Promise<{
   /** Images for the current prompt (existingImages + detected in current prompt) */
@@ -437,10 +444,21 @@ export async function detectAndLoadPromptImages(params: {
     }
   }
 
-  const sanitizedPromptImages = await sanitizeImagesWithLog(promptImages, "prompt:images");
+  const imageSanitization: ImageSanitizationLimits = {
+    maxDimensionPx: params.maxDimensionPx,
+  };
+  const sanitizedPromptImages = await sanitizeImagesWithLog(
+    promptImages,
+    "prompt:images",
+    imageSanitization,
+  );
   const sanitizedHistoryImagesByIndex = new Map<number, ImageContent[]>();
   for (const [index, images] of historyImagesByIndex) {
-    const sanitized = await sanitizeImagesWithLog(images, `history:images:${index}`);
+    const sanitized = await sanitizeImagesWithLog(
+      images,
+      `history:images:${index}`,
+      imageSanitization,
+    );
     if (sanitized.length > 0) {
       sanitizedHistoryImagesByIndex.set(index, sanitized);
     }
diff --git a/src/agents/pi-tools.read.ts b/src/agents/pi-tools.read.ts
index f621ba52b4..1fac1190ba 100644
--- a/src/agents/pi-tools.read.ts
+++ b/src/agents/pi-tools.read.ts
@@ -1,10 +1,11 @@
 import type { AgentToolResult } from "@mariozechner/pi-agent-core";
 import { createEditTool, createReadTool, createWriteTool } from "@mariozechner/pi-coding-agent";
+import type { ImageSanitizationLimits } from "./image-sanitization.js";
+import type { AnyAgentTool } from "./pi-tools.types.js";
+import type { SandboxFsBridge } from "./sandbox/fs-bridge.js";
 import { detectMime } from "../media/mime.js";
 import { sniffMimeFromBase64 } from "../media/sniff-mime-from-base64.js";
-import type { AnyAgentTool } from "./pi-tools.types.js";
 import { assertSandboxPath } from "./sandbox-paths.js";
-import type { SandboxFsBridge } from "./sandbox/fs-bridge.js";
 import { sanitizeToolResultImages } from "./tool-images.js";
 
 // NOTE(steipete): Upstream read now does file-magic MIME detection; we keep the wrapper
@@ -21,6 +22,7 @@ const MAX_ADAPTIVE_READ_PAGES = 8;
 
 type OpenClawReadToolOptions = {
   modelContextWindowTokens?: number;
+  imageSanitization?: ImageSanitizationLimits;
 };
 
 type ReadTruncationDetails = {
@@ -566,6 +568,7 @@ type SandboxToolParams = {
   root: string;
   bridge: SandboxFsBridge;
   modelContextWindowTokens?: number;
+  imageSanitization?: ImageSanitizationLimits;
 };
 
 export function createSandboxedReadTool(params: SandboxToolParams) {
@@ -574,6 +577,7 @@ export function createSandboxedReadTool(params: SandboxToolParams) {
   }) as unknown as AnyAgentTool;
   return createOpenClawReadTool(base, {
     modelContextWindowTokens: params.modelContextWindowTokens,
+    imageSanitization: params.imageSanitization,
   });
 }
 
@@ -614,7 +618,11 @@ export function createOpenClawReadTool(
       const filePath = typeof record?.path === "string" ? String(record.path) : "<unknown>";
       const strippedDetailsResult = stripReadTruncationContentDetails(result);
       const normalizedResult = await normalizeReadImageResult(strippedDetailsResult, filePath);
-      return sanitizeToolResultImages(normalizedResult, `read:${filePath}`);
+      return sanitizeToolResultImages(
+        normalizedResult,
+        `read:${filePath}`,
+        options?.imageSanitization,
+      );
     },
   };
 }
diff --git a/src/agents/pi-tools.ts b/src/agents/pi-tools.ts
index 66f7902695..f4c4eec6cc 100644
--- a/src/agents/pi-tools.ts
+++ b/src/agents/pi-tools.ts
@@ -7,6 +7,9 @@ import {
 } from "@mariozechner/pi-coding-agent";
 import type { OpenClawConfig } from "../config/config.js";
 import type { ToolLoopDetectionConfig } from "../config/types.tools.js";
+import type { ModelAuthMode } from "./model-auth.js";
+import type { AnyAgentTool } from "./pi-tools.types.js";
+import type { SandboxContext } from "./sandbox.js";
 import { logWarn } from "../logger.js";
 import { getPluginToolMeta } from "../plugins/tools.js";
 import { isSubagentSessionKey } from "../routing/session-key.js";
@@ -20,7 +23,7 @@ import {
   type ProcessToolDefaults,
 } from "./bash-tools.js";
 import { listChannelAgentTools } from "./channel-tools.js";
-import type { ModelAuthMode } from "./model-auth.js";
+import { resolveImageSanitizationLimits } from "./image-sanitization.js";
 import { createOpenClawTools } from "./openclaw-tools.js";
 import { wrapToolWithAbortSignal } from "./pi-tools.abort.js";
 import { wrapToolWithBeforeToolCallHook } from "./pi-tools.before-tool-call.js";
@@ -43,8 +46,6 @@ import {
   wrapToolParamNormalization,
 } from "./pi-tools.read.js";
 import { cleanToolSchemaForGemini, normalizeToolParameters } from "./pi-tools.schema.js";
-import type { AnyAgentTool } from "./pi-tools.types.js";
-import type { SandboxContext } from "./sandbox.js";
 import { getSubagentDepthFromSessionStore } from "./subagent-depth.js";
 import {
   applyToolPolicyPipeline,
@@ -300,6 +301,7 @@ export function createOpenClawCodingTools(options?: {
   if (sandboxRoot && !sandboxFsBridge) {
     throw new Error("Sandbox filesystem bridge is unavailable.");
   }
+  const imageSanitization = resolveImageSanitizationLimits(options?.config);
 
   const base = (codingTools as unknown as AnyAgentTool[]).flatMap((tool) => {
     if (tool.name === readTool.name) {
@@ -308,12 +310,14 @@ export function createOpenClawCodingTools(options?: {
           root: sandboxRoot,
           bridge: sandboxFsBridge!,
           modelContextWindowTokens: options?.modelContextWindowTokens,
+          imageSanitization,
         });
         return [workspaceOnly ? wrapToolWorkspaceRootGuard(sandboxed, sandboxRoot) : sandboxed];
       }
       const freshReadTool = createReadTool(workspaceRoot);
       const wrapped = createOpenClawReadTool(freshReadTool, {
         modelContextWindowTokens: options?.modelContextWindowTokens,
+        imageSanitization,
       });
       return [workspaceOnly ? wrapToolWorkspaceRootGuard(wrapped, workspaceRoot) : wrapped];
     }
diff --git a/src/agents/tool-images.e2e.test.ts b/src/agents/tool-images.e2e.test.ts
index e5dff0a9e9..e51f9bc699 100644
--- a/src/agents/tool-images.e2e.test.ts
+++ b/src/agents/tool-images.e2e.test.ts
@@ -49,8 +49,8 @@ describe("tool image sanitizing", () => {
     expect(dropped).toBe(0);
     expect(out.length).toBe(1);
     const meta = await sharp(Buffer.from(out[0].data, "base64")).metadata();
-    expect(meta.width).toBeLessThanOrEqual(2000);
-    expect(meta.height).toBeLessThanOrEqual(2000);
+    expect(meta.width).toBeLessThanOrEqual(1200);
+    expect(meta.height).toBeLessThanOrEqual(1200);
   }, 20_000);
 
   it("shrinks images that exceed max dimension even if size is small", async () => {
@@ -77,8 +77,8 @@ describe("tool image sanitizing", () => {
       throw new Error("expected image block");
     }
     const meta = await sharp(Buffer.from(image.data, "base64")).metadata();
-    expect(meta.width).toBeLessThanOrEqual(2000);
-    expect(meta.height).toBeLessThanOrEqual(2000);
+    expect(meta.width).toBeLessThanOrEqual(1200);
+    expect(meta.height).toBeLessThanOrEqual(1200);
     expect(image.mimeType).toBe("image/jpeg");
   }, 20_000);
 
diff --git a/src/agents/tool-images.ts b/src/agents/tool-images.ts
index e66ff29df2..4851d99ad6 100644
--- a/src/agents/tool-images.ts
+++ b/src/agents/tool-images.ts
@@ -2,6 +2,11 @@ import type { AgentToolResult } from "@mariozechner/pi-agent-core";
 import type { ImageContent } from "@mariozechner/pi-ai";
 import { createSubsystemLogger } from "../logging/subsystem.js";
 import { getImageMetadata, resizeToJpeg } from "../media/image-ops.js";
+import {
+  DEFAULT_IMAGE_MAX_BYTES,
+  DEFAULT_IMAGE_MAX_DIMENSION_PX,
+  type ImageSanitizationLimits,
+} from "./image-sanitization.js";
 
 type ToolContentBlock = AgentToolResult<unknown>["content"][number];
 type ImageContentBlock = Extract<ToolContentBlock, { type: "image" }>;
@@ -13,8 +18,8 @@ type TextContentBlock = Extract<ToolContentBlock, { type: "text" }>;
 //
 // To keep sessions resilient (and avoid "silent" WhatsApp non-replies), we auto-downscale
 // and recompress base64 image blocks when they exceed these limits.
-const MAX_IMAGE_DIMENSION_PX = 1200;
-const MAX_IMAGE_BYTES = 5 * 1024 * 1024;
+const MAX_IMAGE_DIMENSION_PX = DEFAULT_IMAGE_MAX_DIMENSION_PX;
+const MAX_IMAGE_BYTES = DEFAULT_IMAGE_MAX_BYTES;
 const log = createSubsystemLogger("agents/tool-images");
 
 function isImageBlock(block: unknown): block is ImageContentBlock {
@@ -100,7 +105,7 @@ async function resizeImageBase64IfNeeded(params: {
   const maxDim = hasDimensions ? Math.max(width ?? 0, height ?? 0) : params.maxDimensionPx;
   const sideStart = maxDim > 0 ? Math.min(params.maxDimensionPx, maxDim) : params.maxDimensionPx;
   const sideGrid = [sideStart, 1800, 1600, 1400, 1200, 1000, 800]
-    .map((v) => Math.min(params.maxDimensionPx, v))
+    .filter((v) => v > 0 && v <= params.maxDimensionPx)
     .filter((v, i, arr) => v > 0 && arr.indexOf(v) === i)
     .toSorted((a, b) => b - a);
 
@@ -148,7 +153,7 @@ async function resizeImageBase64IfNeeded(params: {
 export async function sanitizeContentBlocksImages(
   blocks: ToolContentBlock[],
   label: string,
-  opts: { maxDimensionPx?: number; maxBytes?: number } = {},
+  opts: ImageSanitizationLimits = {},
 ): Promise<ToolContentBlock[]> {
   const maxDimensionPx = Math.max(opts.maxDimensionPx ?? MAX_IMAGE_DIMENSION_PX, 1);
   const maxBytes = Math.max(opts.maxBytes ?? MAX_IMAGE_BYTES, 1);
@@ -198,7 +203,7 @@ export async function sanitizeContentBlocksImages(
 export async function sanitizeImageBlocks(
   images: ImageContent[],
   label: string,
-  opts: { maxDimensionPx?: number; maxBytes?: number } = {},
+  opts: ImageSanitizationLimits = {},
 ): Promise<{ images: ImageContent[]; dropped: number }> {
   if (images.length === 0) {
     return { images, dropped: 0 };
@@ -211,7 +216,7 @@ export async function sanitizeImageBlocks(
 export async function sanitizeToolResultImages(
   result: AgentToolResult<unknown>,
   label: string,
-  opts: { maxDimensionPx?: number; maxBytes?: number } = {},
+  opts: ImageSanitizationLimits = {},
 ): Promise<AgentToolResult<unknown>> {
   const content = Array.isArray(result.content) ? result.content : [];
   if (!content.some((b) => isImageBlock(b) || isTextBlock(b))) {
diff --git a/src/agents/tools/canvas-tool.ts b/src/agents/tools/canvas-tool.ts
index 77ddb56db4..41475f668b 100644
--- a/src/agents/tools/canvas-tool.ts
+++ b/src/agents/tools/canvas-tool.ts
@@ -1,9 +1,11 @@
+import { Type } from "@sinclair/typebox";
 import crypto from "node:crypto";
 import fs from "node:fs/promises";
-import { Type } from "@sinclair/typebox";
+import type { OpenClawConfig } from "../../config/config.js";
 import { writeBase64ToFile } from "../../cli/nodes-camera.js";
 import { canvasSnapshotTempPath, parseCanvasSnapshotPayload } from "../../cli/nodes-canvas.js";
 import { imageMimeFromFormat } from "../../media/mime.js";
+import { resolveImageSanitizationLimits } from "../image-sanitization.js";
 import { optionalStringEnum, stringEnum } from "../schema/typebox.js";
 import { type AnyAgentTool, imageResult, jsonResult, readStringParam } from "./common.js";
 import { callGatewayTool, readGatewayCallOptions } from "./gateway.js";
@@ -48,7 +50,8 @@ const CanvasToolSchema = Type.Object({
   jsonlPath: Type.Optional(Type.String()),
 });
 
-export function createCanvasTool(): AnyAgentTool {
+export function createCanvasTool(options?: { config?: OpenClawConfig }): AnyAgentTool {
+  const imageSanitization = resolveImageSanitizationLimits(options?.config);
   return {
     label: "Canvas",
     name: "canvas",
@@ -158,6 +161,7 @@ export function createCanvasTool(): AnyAgentTool {
             base64: payload.base64,
             mimeType,
             details: { format: payload.format },
+            imageSanitization,
           });
         }
         case "a2ui_push": {
diff --git a/src/agents/tools/common.ts b/src/agents/tools/common.ts
index a1358b08b7..5dbfd9e6b6 100644
--- a/src/agents/tools/common.ts
+++ b/src/agents/tools/common.ts
@@ -1,5 +1,6 @@
-import fs from "node:fs/promises";
 import type { AgentTool, AgentToolResult } from "@mariozechner/pi-agent-core";
+import fs from "node:fs/promises";
+import type { ImageSanitizationLimits } from "../image-sanitization.js";
 import { detectMime } from "../../media/mime.js";
 import { sanitizeToolResultImages } from "../tool-images.js";
 
@@ -214,6 +215,7 @@ export async function imageResult(params: {
   mimeType: string;
   extraText?: string;
   details?: Record<string, unknown>;
+  imageSanitization?: ImageSanitizationLimits;
 }): Promise<AgentToolResult<unknown>> {
   const content: AgentToolResult<unknown>["content"] = [
     {
@@ -230,7 +232,7 @@ export async function imageResult(params: {
     content,
     details: { path: params.path, ...params.details },
   };
-  return await sanitizeToolResultImages(result, params.label);
+  return await sanitizeToolResultImages(result, params.label, params.imageSanitization);
 }
 
 export async function imageResultFromFile(params: {
@@ -238,6 +240,7 @@ export async function imageResultFromFile(params: {
   path: string;
   extraText?: string;
   details?: Record<string, unknown>;
+  imageSanitization?: ImageSanitizationLimits;
 }): Promise<AgentToolResult<unknown>> {
   const buf = await fs.readFile(params.path);
   const mimeType = (await detectMime({ buffer: buf.slice(0, 256) })) ?? "image/png";
@@ -248,5 +251,6 @@ export async function imageResultFromFile(params: {
     mimeType,
     extraText: params.extraText,
     details: params.details,
+    imageSanitization: params.imageSanitization,
   });
 }
diff --git a/src/agents/tools/nodes-tool.ts b/src/agents/tools/nodes-tool.ts
index 7add129efa..902a453288 100644
--- a/src/agents/tools/nodes-tool.ts
+++ b/src/agents/tools/nodes-tool.ts
@@ -1,6 +1,7 @@
-import crypto from "node:crypto";
 import type { AgentToolResult } from "@mariozechner/pi-agent-core";
 import { Type } from "@sinclair/typebox";
+import crypto from "node:crypto";
+import type { OpenClawConfig } from "../../config/config.js";
 import {
   type CameraFacing,
   cameraTempPath,
@@ -16,9 +17,9 @@ import {
   writeScreenRecordToFile,
 } from "../../cli/nodes-screen.js";
 import { parseDurationMs } from "../../cli/parse-duration.js";
-import type { OpenClawConfig } from "../../config/config.js";
 import { imageMimeFromFormat } from "../../media/mime.js";
 import { resolveSessionAgentId } from "../agent-scope.js";
+import { resolveImageSanitizationLimits } from "../image-sanitization.js";
 import { optionalStringEnum, stringEnum } from "../schema/typebox.js";
 import { sanitizeToolResultImages } from "../tool-images.js";
 import { type AnyAgentTool, jsonResult, readStringParam } from "./common.js";
@@ -100,6 +101,7 @@ export function createNodesTool(options?: {
     sessionKey: options?.agentSessionKey,
     config: options?.config,
   });
+  const imageSanitization = resolveImageSanitizationLimits(options?.config);
   return {
     label: "Nodes",
     name: "nodes",
@@ -250,7 +252,7 @@ export function createNodesTool(options?: {
             }
 
             const result: AgentToolResult<unknown> = { content, details };
-            return await sanitizeToolResultImages(result, "nodes:camera_snap");
+            return await sanitizeToolResultImages(result, "nodes:camera_snap", imageSanitization);
           }
           case "camera_list": {
             const node = readStringParam(params, "node", { required: true });
diff --git a/src/config/schema.help.ts b/src/config/schema.help.ts
index 5f9445d47f..81c194016f 100644
--- a/src/config/schema.help.ts
+++ b/src/config/schema.help.ts
@@ -290,6 +290,8 @@ export const FIELD_HELP: Record<string, string> = {
   "agents.defaults.imageModel.primary":
     "Optional image model (provider/model) used when the primary model lacks image input.",
   "agents.defaults.imageModel.fallbacks": "Ordered fallback image models (provider/model).",
+  "agents.defaults.imageMaxDimensionPx":
+    "Max image side length in pixels when sanitizing transcript/tool-result image payloads (default: 1200).",
   "agents.defaults.cliBackends": "Optional CLI backends for text-only fallback (claude-cli, etc.).",
   "agents.defaults.humanDelay.mode": 'Delay style for block replies ("off", "natural", "custom").',
   "agents.defaults.humanDelay.minMs": "Minimum delay in ms for custom humanDelay (default: 800).",
diff --git a/src/config/schema.labels.ts b/src/config/schema.labels.ts
index 1f351c8efd..95e75b8fb5 100644
--- a/src/config/schema.labels.ts
+++ b/src/config/schema.labels.ts
@@ -204,6 +204,7 @@ export const FIELD_LABELS: Record<string, string> = {
   "agents.defaults.model.fallbacks": "Model Fallbacks",
   "agents.defaults.imageModel.primary": "Image Model",
   "agents.defaults.imageModel.fallbacks": "Image Model Fallbacks",
+  "agents.defaults.imageMaxDimensionPx": "Image Max Dimension (px)",
   "agents.defaults.humanDelay.mode": "Human Delay Mode",
   "agents.defaults.humanDelay.minMs": "Human Delay Min (ms)",
   "agents.defaults.humanDelay.maxMs": "Human Delay Max (ms)",
diff --git a/src/config/types.agent-defaults.ts b/src/config/types.agent-defaults.ts
index 4c9dba0a23..1829c71839 100644
--- a/src/config/types.agent-defaults.ts
+++ b/src/config/types.agent-defaults.ts
@@ -190,6 +190,11 @@ export type AgentDefaultsConfig = {
   timeoutSeconds?: number;
   /** Max inbound media size in MB for agent-visible attachments (text note or future image attach). */
   mediaMaxMb?: number;
+  /**
+   * Max image side length (pixels) when sanitizing base64 image payloads in transcripts/tool results.
+   * Default: 1200.
+   */
+  imageMaxDimensionPx?: number;
   typingIntervalSeconds?: number;
   /** Typing indicator start mode (never|instant|thinking|message). */
   typingMode?: TypingMode;
diff --git a/src/config/zod-schema.agent-defaults.ts b/src/config/zod-schema.agent-defaults.ts
index 2508179707..d99af6dc2b 100644
--- a/src/config/zod-schema.agent-defaults.ts
+++ b/src/config/zod-schema.agent-defaults.ts
@@ -126,6 +126,7 @@ export const AgentDefaultsSchema = z
     humanDelay: HumanDelaySchema.optional(),
     timeoutSeconds: z.number().int().positive().optional(),
     mediaMaxMb: z.number().positive().optional(),
+    imageMaxDimensionPx: z.number().int().positive().optional(),
     typingIntervalSeconds: z.number().int().positive().optional(),
     typingMode: z
       .union([