When loading a MP3 file that has an embedded image with type set to 0 ("other"), Picard will load this image as type "sticker".

Likewise the ID3 type 6 "Media (e.g. label side of CD)" gets loaded as "track", while it probably better should be loaded as "medium".

This works as expected when using Python 3.5, but breaks in Python 3.6 and later.