Flickr, Picasa etc

So far I have successfully uploaded some photos to Flickr, with the intention of easily making a collage for my daughter. However, I am still pfaffing around with all this many hours later. I could not see where in Flickr I could turn these images into a collage, but managed to find an interesting site called BigHugeLabs, which, surprisingly, is not a site dedicated to overweight Labrador dogs, but photos. I've already had a bit of a look around, managed to upload a photo set - but it didn't upload the whole set, so now it's back to the drawing board. I can see this "simple" exercise could take quite some time to accomplish (for me anyway !) but hopefully once I've sussed it out I'll be able to do it easily the next time...