You can use this technique (available only for Pro Account users) :
1. In the skin selection page, find a parameter called “Album Cover Art” in the change it to custom.
2. Continue to upload your music files and also upload the cover art image files
3. In the text and reorder page, organize the items in pairs : a. image file, music file, image file, music file etc.
Note that if you want to have the same image for few or all music files then you can upload the image only once and order like this :
a. image file, music file, music file music file etc.
Here is an example: http://www.cincopa.com/media-platform/skins/medium-music-player-with-menu