Ok, this needs some explanation.
Basically, the Headunit of my new car (Renault EasyLink) has the ability to display cover art of music, but ONLY if tagged in ID3 format.
.flac files will play but not display cover art.
If I use EAC and select to add ID3 tags to the ripped flac files everything works.
However, I usually do some editing to my music, I don't just rip from CD and call it a day (I usually will normalize all files to around 89dB so even the quietest track on my USB drive won't clip, + I add a portion of dithering noise before the track otherwise the HU will cut the first beat sometimes) and then I use mp3 tag to re-do the tagging job.
Please add a function like "force ID3 tags (not recommended)" ! I know this doesn't make sense in most other cases.