Implements GET for images

album.go

@@ -106,8 +106,8 @@ func (a *Album) String() string {
 
 var rxExt = regexp.MustCompile(`\.([0-9]+)([a-zA-Z]+)\z`)
 
-func (a *Album) CoverExt() string {
-	ext := path.Ext(a.CoverURL)
+func AlbumCoverExt(URL string) string {
+	ext := path.Ext(URL)
 	m := rxExt.FindStringSubmatch(ext)
 	if m != nil {
 		ext = "." + m[2]