I hope I didn't ruin the rest of your work week.  I think mine already is.  The only rule I have (subject to anything from Van) is to be sensible.  Nobody wants to see any Pete Carroll porn or anything incredibly nasty.  Try to keep it SFW.  If you absolutely cannot because you came up with something hilarious, just don't post it outright.  Link to it and make sure anyone who clicks knows it's NSFW.  As in not suitable for work, but if you're proficient enough with photoshop to do what we all want you to do, you knew that.  A long time ago.  When you clicked that one thing.  What were you thinking?  Anyway, photoshop away, people.

For example, you could paint a vignette of Carroll letting off some steam after Seattle's loss to Denver in week 2: