fix(img):Prevent thumbnail generation for large images

img/service.go

@@ -19,6 +19,15 @@ import (
 // ErrUnsupportedFormat means the given image format is not supported.
 var ErrUnsupportedFormat = errors.New("unsupported image format")
 
+// ErrImageTooLarge means the image is too large to create a thumbnail.
+var ErrImageTooLarge = errors.New("image too large for thumbnail generation")
+
+// Maximum dimensions for thumbnail generation to prevent server crashes
+const (
+	MaxImageWidth  = 10000
+	MaxImageHeight = 10000
+)
+
 // Service
 type Service struct {
 	sem semaphore.Semaphore
@@ -187,11 +196,17 @@ func (s *Service) detectFormat(in io.Reader) (Format, io.Reader, error) {
 	buf := &bytes.Buffer{}
 	r := io.TeeReader(in, buf)
 
-	_, imgFormat, err := image.DecodeConfig(r)
+	imgConfig, imgFormat, err := image.DecodeConfig(r)
 	if err != nil {
 		return 0, nil, fmt.Errorf("%s: %w", err.Error(), ErrUnsupportedFormat)
 	}
 
+	// Check if image dimensions exceed maximum allowed size
+	if imgConfig.Width > MaxImageWidth || imgConfig.Height > MaxImageHeight {
+		return 0, nil, fmt.Errorf("image dimensions %dx%d exceed maximum %dx%d: %w",
+			imgConfig.Width, imgConfig.Height, MaxImageWidth, MaxImageHeight, ErrImageTooLarge)
+	}
+
 	format, err := ParseFormat(imgFormat)
 	if err != nil {
 		return 0, nil, ErrUnsupportedFormat