minor addition to #8238

app/post.go

@@ -894,14 +894,10 @@ func (a *App) ImageProxyAdder() func(string) string {
 	}
 
 	return func(url string) string {
-		if url == "" || strings.HasPrefix(url, siteURL) || strings.HasPrefix(url, proxyURL) {
+		if url == "" || url[0] == '/' || strings.HasPrefix(url, siteURL) || strings.HasPrefix(url, proxyURL) {
 			return url
 		}
 
-		if url[0] == '/' {
-			url = siteURL + url[1:]
-		}
-
 		switch proxyType {
 		case "atmos/camo":
 			mac := hmac.New(sha1.New, []byte(options))