"Bob and I" or "Bob and me" when describing a picture
Solution 1:
The rule here is very simple: the correct word is the one you'd use if there were no "Bob" involved -- so "I went to the store" becomes "Bob and I went to the store," and "She kissed me" becomes "She kissed Bob and me."
So what would you label a picture of just yourself? "This is me" or "This is I"? It's the first one, of course, so the proper caption is "(This is) Bob and me."