To photobomb is to appear in somebody else's picture on purpose. Photobomb the group shot.
It has to be discovered later, since being noticed at the time spoils it. To photobomb well is to do nothing at all except be somewhere unexpected.
1verbphotobombTo appear in somebody else's picture on purpose.
“A seal photobombed the entire wedding party.”
photobomb is an action.
From photo + bomb.
Etymology from Wiktionary, CC BY-SA