@david Very true, and I tried to have a look at how to do that. But I quickly saw it would take me a lot of time , disk space, and CPU time only to get a smart collage (because my sample being not billions of images, but hundreds, maximum a thousand). I'll also would have to provide description for each picture. Well, I think it's at this point my laziness just quick-in and I abandoned the idea. Maybe something for the future if it get simpler. 🙂