Yeah I found them. There is subfolders for each contact, and they contain the pictures as well as some log files. I just can't imagine a way to see them. Hidden folders are hidden () by default in the (default) file manager. So only way to even list those pics is to use terminal. Could I somehow broaden the gallery app to seek for photos from /home/user/.purple/username ? Or make a symbolic link to somewhere else which is already included to gallery app pic folders?