better reusing media methods

media/media.go

@@ -168,12 +168,7 @@ func (ms *MediaSource) ThumbMax(m Media, maxDim int) (string, image.Rectangle, e
 		return "", image.ZR, err
 	}
 
-	img, _, err := image.Decode(f)
-	if err != nil {
-		return "", image.ZR, err
-	}
-
-	src, err := ms.ThumbImage(img, m, size)
+	src, err := ms.thumbReader(f, m, size)
 	return src, size, err
 }
 
@@ -207,7 +202,11 @@ func (ms *MediaSource) Thumb(m Media, size image.Rectangle) (string, error) {
 	}
 	defer f.Close()
 
-	img, _, err := image.Decode(f)
+	return ms.thumbReader(f, m, size)
+}
+
+func (ms *MediaSource) thumbReader(r io.Reader, m Media, size image.Rectangle) (string, error) {
+	img, _, err := image.Decode(r)
 	if err != nil {
 		return "", err
 	}
@@ -216,7 +215,6 @@ func (ms *MediaSource) Thumb(m Media, size image.Rectangle) (string, error) {
 }
 
 func (ms *MediaSource) ThumbImage(img image.Image, m Media, size image.Rectangle) (string, error) {
-
 	thumbLoc := ms.ThumbFilename(m, size)
 	os.MkdirAll(path.Dir(thumbLoc), 0755)
 	fthumb, err := os.OpenFile(thumbLoc, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0655)