feat: add image file validation and format detection for image generation

## CHANGES

• Add image file path validation with extension checking
• Implement dynamic output format detection from file extensions
• Update BuildChatOptions method to return error for validation
• Add comprehensive test coverage for image file validation
• Upgrade YAML library from v2 to v3
• Update shell completions to reflect supported image formats
• Add error handling for existing file conflicts
• Support PNG, JPEG, JPG, and WEBP image formats

plugins/ai/openai/openai_image.go

@@ -8,6 +8,7 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"strings"
 
 	"github.com/danielmiessler/fabric/common"
 	"github.com/openai/openai-go/responses"
@@ -17,15 +18,37 @@ import (
 const ImageGenerationResponseType = "image_generation_call"
 const ImageGenerationToolType = "image_generation"
 
+// getOutputFormatFromExtension determines the API output format based on file extension
+func getOutputFormatFromExtension(imagePath string) string {
+	if imagePath == "" {
+		return "png" // Default format
+	}
+
+	ext := strings.ToLower(filepath.Ext(imagePath))
+	switch ext {
+	case ".png":
+		return "png"
+	case ".webp":
+		return "webp"
+	case ".jpg":
+		return "jpeg"
+	case ".jpeg":
+		return "jpeg"
+	default:
+		return "png" // Default fallback
+	}
+}
+
 // addImageGenerationTool adds the image generation tool to the request if needed
 func (o *Client) addImageGenerationTool(opts *common.ChatOptions, tools []responses.ToolUnionParam) []responses.ToolUnionParam {
 	// Check if the request seems to be asking for image generation
 	if o.shouldUseImageGeneration(opts) {
+		outputFormat := getOutputFormatFromExtension(opts.ImageFile)
 		imageGenTool := responses.ToolUnionParam{
 			OfImageGeneration: &responses.ToolImageGenerationParam{
 				Type:         ImageGenerationToolType,
 				Model:        "gpt-image-1",
-				OutputFormat: "png",
+				OutputFormat: outputFormat,
 				Quality:      "auto",
 				Size:         "auto",
 			},

plugins/ai/openai/openai_image_test.go

@@ -112,3 +112,109 @@ func TestBuildResponseParams_WithBothSearchAndImage(t *testing.T) {
 	assert.True(t, hasSearchTool, "Should have web search tool")
 	assert.True(t, hasImageTool, "Should have image generation tool")
 }
+
+func TestGetOutputFormatFromExtension(t *testing.T) {
+	tests := []struct {
+		name           string
+		imagePath      string
+		expectedFormat string
+	}{
+		{
+			name:           "PNG extension",
+			imagePath:      "/tmp/output.png",
+			expectedFormat: "png",
+		},
+		{
+			name:           "WEBP extension",
+			imagePath:      "/tmp/output.webp",
+			expectedFormat: "webp",
+		},
+		{
+			name:           "JPG extension",
+			imagePath:      "/tmp/output.jpg",
+			expectedFormat: "jpeg",
+		},
+		{
+			name:           "JPEG extension",
+			imagePath:      "/tmp/output.jpeg",
+			expectedFormat: "jpeg",
+		},
+		{
+			name:           "Uppercase PNG extension",
+			imagePath:      "/tmp/output.PNG",
+			expectedFormat: "png",
+		},
+		{
+			name:           "Mixed case JPEG extension",
+			imagePath:      "/tmp/output.JpEg",
+			expectedFormat: "jpeg",
+		},
+		{
+			name:           "Empty path",
+			imagePath:      "",
+			expectedFormat: "png",
+		},
+		{
+			name:           "No extension",
+			imagePath:      "/tmp/output",
+			expectedFormat: "png",
+		},
+		{
+			name:           "Unsupported extension",
+			imagePath:      "/tmp/output.gif",
+			expectedFormat: "png",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := getOutputFormatFromExtension(tt.imagePath)
+			assert.Equal(t, tt.expectedFormat, result)
+		})
+	}
+}
+
+func TestAddImageGenerationToolWithDynamicFormat(t *testing.T) {
+	client := NewClient()
+
+	tests := []struct {
+		name           string
+		imageFile      string
+		expectedFormat string
+	}{
+		{
+			name:           "PNG file",
+			imageFile:      "/tmp/output.png",
+			expectedFormat: "png",
+		},
+		{
+			name:           "WEBP file",
+			imageFile:      "/tmp/output.webp",
+			expectedFormat: "webp",
+		},
+		{
+			name:           "JPG file",
+			imageFile:      "/tmp/output.jpg",
+			expectedFormat: "jpeg",
+		},
+		{
+			name:           "JPEG file",
+			imageFile:      "/tmp/output.jpeg",
+			expectedFormat: "jpeg",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			opts := &common.ChatOptions{
+				ImageFile: tt.imageFile,
+			}
+
+			tools := client.addImageGenerationTool(opts, []responses.ToolUnionParam{})
+
+			assert.Len(t, tools, 1, "Should have one tool")
+			assert.NotNil(t, tools[0].OfImageGeneration, "Should be image generation tool")
+			assert.Equal(t, tt.expectedFormat, tools[0].OfImageGeneration.OutputFormat, "Output format should match file extension")
+		})
+	}
+}