diff --git a/api/user.go b/api/user.go
index b7d39a7..0107f10 100644
--- a/api/user.go
+++ b/api/user.go
@@ -173,7 +173,7 @@ func parseSubmission(value gjson.Result) Submission {
 			Url: strings.ReplaceAll(c.Get("url").String(), "https://i.imgur.com", ""),
 		}
 		// Replace with thumbnails here because it's easier.
-		if cover.Url[len(cover.Url)-3:] == "mp4" {
+		if strings.HasSuffix(cover.Url, ".mp4") {
 			cover.Url = cover.Url[:len(cover.Url)-3] + "webp"
 		}
 	default: