No cover on desk vinyl played

On Mac OS X Yosemite (10.10.1 release), with DJay 4.2.3, I wondered why sometimes I met a bug: when I add a cover to my track which had no cover yet, it appears on iTunes, but it’s not take in charge on my DJ software. My desk vinyl still stay white when I play the tune. Even if I restart Djay or refresh my library before.
Did I miss something ?