Here's what you do.
You take the base picture, and add a little bit to it. Each time someone else adds to it, you add to theirs. Eventually we'll have a picture with all sorts of new content from each person.
Let's make this normal classroom a little more fun...
(You can use any editing software, but please make it a jpg when reposting. It makes it easier for all of us
If you're not sure what the heck this is, check out a thread from my school's forum for an example