Edit: I just figured out that the MP3 cover picture is shown in the preview / in view mode and not as file thumbnail in browser.
XnView 1.98 beta 1 changelog wrote:* Thumbnail for mp3
I assume this means the ID3 album cover picture embedded into MP3 audio files, but can't get it to work. There's no thumbnail checkbox for Audio files File List options.
The only way to get the MP3 thumbnails to show up is to disable "Recognize only by extension" which works "out-of-the-box" in previous XnView versions too. Is this how it's supposed to work?