karsten75 Okay, I can follow it here as well. The files have different file sizes after resizing:
With animation: 277 KB (284,125 bytes)
Without animation: 15.1 KB (15,534 bytes)
It looks like only the first image is changed and saved.
Maybe an effect of the change to the Slika library. You could post a bug report on Github.
saggi
Edit: The converted file is a GIF87a, the originals are a GIF89a