Your problem is that the drawing events aren't being processed because you are busy making thumbnails, what you want to do is include a while gtk.events_pending(): gtk.main_iteration(False) in your thumbnail loop. Check out the link below for more info. http://live.gnome.org/PyGTK/FAQ/SignalHandling#head-614693e5763ca2b3f422ec197e482070ea4f9800 John