If you're not saying 'Om Nom Nom Nom' out loud at the same time as looking at these pictures then you're doing it wrong.The people behind this Interwebs fad seem to be (or be affiliated with) the Triforce, Three Panel Hollywood, One Life Left, Encyclopedia Dramatica. Omnomnomnom has a forum where you can add/suggest new pictures.
If you were wondering what these pictures would look like in a tangentially related annoying video format, wonder no more. I got the site to repeat, but hopefully they will add more to their repertoire. Here are a few of my favorites: