diff --git a/src/pomf.ts b/src/pomf.ts
index e770721..d0b31dd 100644
--- a/src/pomf.ts
+++ b/src/pomf.ts
@@ -16,12 +16,12 @@ settings.subscribe(b => {
 });
 
 const getExt = (fn: string) => {
-    const isDum = fn!.match(/^([a-z0-9]{6}\.(?:jpe?g|png|webm|gif))/gi);
+    const isDum = fn!.match(/^[a-z0-9]{6}\./i);
     const isB64 = fn!.match(/^((?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=))?\.(gif|jpe?g|png|webm)/);
     const isExt = fn!.match(/\[.*=(.*)\]/);
     let ext;
     if (isDum) {
-        ext = isDum[0];
+        ext = fn.split('.').slice(0, -1).join('.');
     } else if (isB64) {
         ext = atob(isB64[1]);
     } else if (isExt) {