I can’t check the behavior on Ubuntu 18.04 default. I just can compare with Ubuntu 16.04 Unity.
There, in Nautilus, my music files do not show their generic mimetype icon but the cover / album art - when this picture is embedded in file ( mp3 can do that ).
In UBudgie 18.04, I only have generic mimetype icons for all music files, even those with embedded pictures.
I LOVE to have pictures embedded in mp3 because thanks to that, my music keeps its face whatever the device or system I play it.
Is this a new « limitation » of Nautilus ? How does this work in 19.04/10 with Nemo ?