changing to do cover art from imdb would be a relatively simple fix for the web admin.
However, there is a mechanism that you guys aren't aware of as well... the External Media Identifier.
the EMI is called when discs are inserted into your DVD drive, either audio or DVD video.
The disc's fingerprint is calculated, and results are sent off to Windows Media Services (yes..), and a resulting cover art is retrieved, along with data for chapters, tracks, etc. There is currently not a free service out there that does this.
As for updating cover art on the GUI, we have to be very careful about adding user facing complexity. With the web admin, all administration functions are clearly separated from USING the system, and it should stay this way... With that said, the web admin needs some serious rewriting, retrofitting, etc.. Thanks Jondecker76 for working on this!