/usr/lib/flipcalendar/themes/default/ The image needs to be case sensitive so you might have to change the above image from calendar.PGN to calendar.pgn I think you also have to change the permissions for the graphic as well (write and exec). I can't really help you with that to be honest since I'm no good with the command line. I just use EmelFM2 while being root, click on the menu button, change permissions, then finally check mark all of the boxes. Good luck on my bad advice.