For Example, the first picture could be of a piece of paper, the next is some scissors, then a rock, and then a hammer, then a big magnet, and so on. Or it could be a witch, then a house, then a house fire and so on.
It should be able to go on indefinitely, as long as people don't start going astronomical and keep it fairly simple. But there shouldn't be anything that ends it all as long as you are imaginative. Also try to make it make sense and be clever, an elephant followed by a mouse is good, but an elephant followed by a meteor really isn't.
Also be SFW, and feel free to post a caption or a line or two to set it up if it isn't inherently obvious how it will defeat the previous post.
I'll start with:
A Tree!
