Lots of times, albums are uploaded with no scans at all or maybe just really tiny ones. Where do you go usually to get your covers? What sites have the best scans, widest selection, or most complete album art?
For me, my first stop would be www.allcdcovers.com. They have a pretty huge selection of CDs as well as DVDs now. While some of the scans are not really high quality, the sizes generally range around 1200 to 1400 pixels. And they include a lot of the album art like back cover, inlays, and CD itself. Most scans will be downloaded as jpgs.
The downside here is that after about 8 or 10 downloads, you get hit with an anti-robot "please enter the below code to continue" prompt and you end up downloading a huge bmp file instead of a nice jpg. After this download, you're back to pulling down jpgs again for a while. So it's really just a bump in the road if you're going after all the art for somebody's discography, for example. Still worth the trip.
dr.g

how do I embed them into a mp3?

You can always just use Album Cover applications that do it automatically for you... I use Coverscout.

this is very useful, i use this fr album covers and editing all the info of songs!!!!

me too..!!

Wow .. that was really useful info Doc. THank you! I've been downloading my album art either from Wikia (from a search on the specific album/artist), or from Microsoft's database (cover only). I'll check out allcdcovers.com! I'd like to get more of the album materials (back cover at least, inlays if possible)!

Yep i use google for covers too.

Google Images. Tuneup sucks.

agreed. google is wonderful

google chrome for me or i rip my own...
just search for the name of the album and/or artist. then click image

Ditto
Ditto