Aye, it's possible to add album art in Winamp too, however we shouldn't need to use another program to add it.
I know we programmed some of the album art add-ins for Winamp in the past and used a few logic steps including named files.
I think it should work independent of named files though and pick up the basic files such as jpg, png, bmp etc...
If there are various sizes show the biggest one unless the space it's going into is too small. i.e. no point in putting in a 200*200 image into a 60*60 space (might aswell use the smallest version of say 75*75 or nearest)
Although in the song info panel use the biggest version.
If not various sizes then use the same 1 for all.
Even though I have album art for all my cds/albums a lot of them don't have the mp3s/mp4/m4as tagged with the album art so none show up, not a biggie really.
I'm surprised we missed this functionality after all this time lol