I like to think of it as making multiple copies of an image and applying various filters to them. You basically get a complete copy of the original because it's too much of a hassle to create another image from scratch, and you edit it as you desire, all the while keeping the old one. You then go around telling everyone the new image is better because you increased its brightness, resolution, etc., and that everyone who still uses the old one as their wallpaper or something should switch to your new and improved one instead. All the pictures are open to everyone though, so while everyone has a copy of your new one, they have the option of not using it, or completely abandoning the old one for it. Now, instead of everyone in the group having the same wallpaper, the group gets rather fragmented.
That's about as simple as I can explain it. Sorry if my analogy is bad lol.
I think that's a really fun analogy and an easy way to understand it.