I have found the following video, which shows a transition effect which is based on a sort of morph-based interpolation between two images:
http://www.cs.cmu.edu/afs/andrew/scs/cs/15-463/f07/proj_final/www/amichals/one.mpg
Is there a tool for easily creating a GIF (or a video) with a similar effect (so no fading), starting from two images (start and end)?