Hed Kandi is a label, but there is no section for Label artwork (except for logos)
It's not about how discogs sees them, it's how they are entered on Musicbrainz, and therefore here on fanart.
There are Hed Kandi Compilations under Various Artists (e.g. Twisted Disco), but there are also DJ mixes on the Hed Kandi label (e.g. Miguel Migs - Those Things)
So, the background artwork definately wouldn't be accepted for Various Artists. They would also be denied for the individual artists, as it would be the same as uploading say Warner Bros artwork to Prince's page just because he has recorded stuff on their label.
It's a shame though, as I'm into dance music myself and really like Hed Kandi artwork!