So I've been scouring this forum for the past few days trying to figure out a fix for the problem I have, which is when I play a song the Album Art displayed for the current song "blinks" - it looks like the J3 screen dims, then becomes bright again. This cycles about every 10 seconds. It annoyed the crap out of me.
Then I realized what the problem was, which is embedding more than 1 Album Art picture per song; It causes the J3 to switch between the art embedded in the song every 10 seconds or so. This can happen if you use a mp3 Tag Editor (e.g. Mp3tagger v2.49, which is the one I use) to modify the ID3 tag or add album art without first removing the pre-existing art.
So, long story short - if you guys notice this problem, make sure your mp3s have only 1 Album Art embedded per song.