Jackets must be *.bmp (default you can change in Features) and must have sale name that album folder. EX: Jacket of folder named "Sincemilia - Résistance" must be "Sincemilia - Résistance.bmp"
MP3player n°1 :
MP3player n°2 :
Listof music folders : Type "FolderName1,FolderName2,..
(And folders which have "Mp3" in title) In music folders you can see albums jackets
You don't have to edit this list, you can just click on folder icon in the webview