🖼️ docs: add clientImageResize configuration (#333)

pages/docs/configuration/librechat_yaml/object_structure/config.mdx

@@ -149,9 +149,61 @@ see: [Web Search Object Structure](/docs/configuration/librechat_yaml/object_str
     ['endpoints', 'Record/Object', 'Specifies file handling configurations for individual endpoints, allowing customization per endpoint basis.', ''],
     ['serverFileSizeLimit', 'Number', 'The maximum file size (in MB) that the server will accept. Applies globally across all endpoints unless overridden by endpoint-specific settings.', ''],
     ['avatarSizeLimit', 'Number', 'Maximum size (in MB) for user avatar images.', ''],
+    ['clientImageResize', 'Object', 'Configures client-side image resizing to optimize file uploads and prevent upload errors due to large image sizes.', ''],
   ]}
 />
 
+## clientImageResize
+
+**Key:**
+<OptionTable
+  options={[
+    ['clientImageResize', 'Object', 'Configures client-side image resizing to optimize file uploads and prevent upload errors due to large image sizes.', ''],
+  ]}
+/>
+
+**Subkeys:**
+<OptionTable
+  options={[
+    ['enabled', 'Boolean', 'Enables or disables client-side image resizing functionality. Default: false.', 'enabled: true'],
+    ['maxWidth', 'Number', 'Maximum width in pixels for resized images. Images wider than this will be resized. Default: 1920.', 'maxWidth: 1024'],
+    ['maxHeight', 'Number', 'Maximum height in pixels for resized images. Images taller than this will be resized. Default: 1080.', 'maxHeight: 768'],
+    ['quality', 'Number', 'JPEG compression quality (0.1 to 1.0). Higher values mean better quality but larger file sizes. Default: 0.8.', 'quality: 0.9'],
+    ['compressFormat', 'String', 'Output format for compressed images. Options: "jpeg", "webp". Default: "jpeg".', 'compressFormat: "webp"'],
+  ]}
+/>
+
+**Description:**
+
+The `clientImageResize` configuration enables automatic client-side image resizing before upload. This feature helps:
+
+- **Prevent upload failures** due to large image files exceeding server limits
+- **Reduce bandwidth usage** by compressing images before transmission  
+- **Improve upload performance** with smaller file sizes
+- **Maintain image quality** while optimizing file size
+
+When enabled, images that exceed the specified `maxWidth` or `maxHeight` dimensions are automatically resized on the client side before being uploaded to the server. The resizing maintains the original aspect ratio while ensuring the image fits within the specified bounds.
+
+**Example:**
+```yaml filename="clientImageResize"
+fileConfig:
+  clientImageResize:
+    enabled: true
+    maxWidth: 1920
+    maxHeight: 1080
+    quality: 0.8
+    compressFormat: "jpeg"
+```
+
+**Notes:**
+
+- Only applies to image files (JPEG, PNG, WebP, etc.)
+- Resizing occurs automatically when images exceed the specified dimensions
+- Original aspect ratio is preserved during resizing
+- The feature works with all supported image upload endpoints
+- Quality setting only applies to JPEG and WebP formats
+- Setting quality too low (< 0.5) may result in noticeable image degradation
+
 see: [File Config Object Structure](/docs/configuration/librechat_yaml/object_structure/file_config)
 
 ## rateLimits