Can I upload custom album art?

Yes, you are able to display custom album art as well as a custom purchase URL. There are 2 ways to specify custom album art, these are show below:

Folder Images
This data source will search for JPEG (.jpg) images saved in your media folders in the following order:

In a JPEG file with the same name as the MP3 file.
Example:
Uploaded MP3 filename: Album Name\demo_track.mp3
Cover image filename: Album Name\demo_track.jpg

In a JPEG file named albumartsmall.jpg in the same folder as the MP3 file. (This is a standard filename also used by Windows explorer.)
Example:
Uploaded MP3 filename: Album Name\demo_track.mp3
Cover image filename: Album Name\albumartsmall.jpg

In a JPEG file named folder.jpg in the same folder as the MP3 file. (Much like albumartsmall.jpg, this is a standard filename also used by Windows explorer.)
Example:
Uploaded MP3 filename: Album Name\demo_track.mp3
Cover image filename: Album Name\folder.jpg

In any JPEG file in the same folder as the MP3 file. If more than one JPEG exists, preference will be given to those with filenames containing the words “front” or “cover”. If no filenames contain “front” or “cover”, the first image the Media Control Panel finds will be used.
Example:
Uploaded MP3 filename: Album Name\demo_track.mp3
Cover image filename: Album Name\any_filename_will_work.jpg

Custom URL (and Purchase URL)
Configures the use of custom album covers and data. Custom album covers and data can be specified in the media library by right-clicking on an album and selecting Edit album details.
This is best used if hosting the images off the AutoDJ server. This section also allows you to edit the purchase URL of the album.