diff --git a/lib/pleroma/mime.ex b/lib/pleroma/mime.ex
index 84fb536e0..36771533f 100644
--- a/lib/pleroma/mime.ex
+++ b/lib/pleroma/mime.ex
@@ -102,10 +102,18 @@ defp check_mime_type(<<0x4F, 0x67, 0x67, 0x53, 0x00, 0x02, 0x00, 0x00, _::binary
     "audio/ogg"
   end
 
-  defp check_mime_type(<<0x52, 0x49, 0x46, 0x46, _::binary>>) do
+  defp check_mime_type(<<"RIFF", _::binary-size(4), "WAVE", _::binary>>) do
     "audio/wav"
   end
 
+  defp check_mime_type(<<"RIFF", _::binary-size(4), "WEBP", _::binary>>) do
+    "image/webp"
+  end
+
+  defp check_mime_type(<<"RIFF", _::binary-size(4), "AVI.", _::binary>>) do
+    "video/avi"
+  end
+
   defp check_mime_type(_) do
     @default
   end