diff --git a/coolq/bot.go b/coolq/bot.go
index 0a2fffa..6818e1c 100644
--- a/coolq/bot.go
+++ b/coolq/bot.go
@@ -159,7 +159,7 @@ func (bot *CQBot) uploadLocalImage(target message.Source, img *LocalImageElement
 	}
 	if mt == "image/webp" && base.ConvertWebpImage {
 		newname := img.File + ".png"
-		err := global.ConvertImagePng(img.File, newname)
+		err := global.ConvertImage(img.File, newname)
 		if err != nil {
 			return nil, errors.Wrap(err, "convert webp image error")
 		}
diff --git a/global/codec.go b/global/codec.go
index 4ef6bbc..ebdb241 100644
--- a/global/codec.go
+++ b/global/codec.go
@@ -47,7 +47,7 @@ func ExtractCover(src string, target string) error {
 	return errors.Wrap(cmd.Run(), "extract video cover failed")
 }
 
-func ConvertImagePng(src string, target string) error {
-	cmd := exec.Command("ffmpeg", "-i", src, "-y", "-f", "png", target)
+func ConvertImage(src string, target string) error {
+	cmd := exec.Command("ffmpeg", "-i", src, "-y", target)
 	return errors.Wrap(cmd.Run(), "convert image to png failed")
 }