I found this which may be of some use.
Adding Folder Album Art to Music
First things first, lets add some Album Art to our MP3s. The PS3 reads the album cover info from the files/songs themselves vs a folder.jpg like most music players will read from. So to get your album art to show you will actually need to embed the album art into the file.
This can be done a few ways using different software. i prefer to use the free way, Windows Media Player 11 since i use WMP as my main syncing application and have been for the last 4 years (had a WM5 phone, PPC device, use office). The easiest way to manually add album art in media player 11 is to have WMP11 in the Music library, and then sorted by Album and use the large thumbnails view. Then open up IE/ Firefox and use google images to find the album art. Once you find the art via google images, right click the photo, choose Copy and then in WMP11, right click where it says add "Paste Art Here" and choose "Paste Album Art". It will embed the art to all of the songs under this album. Once you are done, it may take a few hours for Media Player to embed the new art into the actual mp3s.
Source - http://www.tech-recipes.com/rx/2258/...eo_tips_tricks