diff --git a/src/modules/fedimbed.js b/src/modules/fedimbed.js
index 7d20d7f..fa2c11b 100644
--- a/src/modules/fedimbed.js
+++ b/src/modules/fedimbed.js
@@ -226,6 +226,7 @@ async function processUrl(msg, url) {
               attachment.pleroma?.mime_type ?? attachment.type.indexOf("/") > -1
                 ? attachment.type
                 : attachment.type +
+                  "/" +
                   (url.match(/\.([a-z0-9]{3,4})$/)?.[0] ??
                   attachment.type == "image"
                     ? "png"
@@ -469,6 +470,7 @@ async function processUrl(msg, url) {
             attachment.type.indexOf("/") > -1
               ? attachment.type.replace("/", ".")
               : attachment.type +
+                "." +
                 (url.match(/\.([a-z0-9]{3,4})$/)?.[0] ?? "mp4"),
           contents: file,
         });
@@ -504,6 +506,7 @@ async function processUrl(msg, url) {
                   .replace("vnd.wave", "wav")
                   .replace("x-wav", "wav")
               : attachment.type +
+                "." +
                 (url.match(/\.([a-z0-9]{3,4})$/)?.[0] ?? "mp3"),
           contents: file,
         });