Citations:photobomb

Noun: "an act of photobombing"

 * 2012 — "Best photobomb EVER! Returning Navy sailor surprises grandmother by jumping in a photo on her birthday", Daily Mail, 27 March 2012:
 * His [sic] person who uploaded the video, who appears to be Ellis' father, wrote in his description that the photobomb was not the only surprise welcome they staged that day.
 * 2012 — Lucy Carne, "John Coates' son photobombs the Queen at London Olympics Opening Ceremony", The Telegraph (Sydney), 1 August 2012:
 * Twitter was also filled with comments about the Queen photobomb.

Noun: "a photo containing someone or something that is photobombing"

 * 2008 — Burt Constable, "Phelps fatigue, feuds and flaps mean Olympics can't end soon enough", Daily Herald, 21 August 2008:
 * Athletes are celebrated just for competing. Russian gymnast Anna Pavlova, who recorded an imperfect 0.00 for one of her vault attempts, could try to land a photobomb of herself mugging in the background of all those photos that will be taken of Phelps lugging around his gold.
 * 2012 — Andrea Denhoed, "A Few Words About The Stingray Photobomb", The New Yorker, 9 October 2012:
 * Today, the photo can be labelled a photobomb, which implies a narrative of surreptitious sabotage, connects the stingray to a whole tribe of obnoxious pranksters, and makes the ray look like his smile might contain a hint of frat-boyish dissolution.

Verb: "to unexpectedly appear in a photograph, especially so as to ruin the picture"

 * 2010 — Renato Gandia, "Labour Day rivalry rekindled among fans", Calgary Sun, 6 September 2010 (image caption):
 * Edmonton Eskimos fans taunt a Calgary Stampeders mascot who photobombed  their group photo.
 * 2011 — Ted Casablanca & John Boone, "Caught! Is Matthew Morrison Too Hot to Handle?", E! Online, 31 May 2011:
 * Modern Familys Eric Stonestreet snuck into a few snapshots too, photobombing' some of the other celebs and making funny faces.
 * 2012 — Chris Cannon & Brian Calvert, America, But Better: The Canada Party Manifesto, Douglas & McIntyre (2012), ISBN 9781771000628, page 23:
 * For many, Speed Voting will present an exciting chance to smell a millionaire. For others, an opportunity to photobomb a soon-to-be-jailed United States senator.
 * 2012 — Brad Getty, Dads Are the Original Hipsters, Chronicle Books (2012), ISBN 9781452114033, page 112:
 * Your dad photobombed before you did and his friends have the pictures to prove it.
 * 2012 — Let's Go Budget Rome, Let's Go Publications (2012), ISBN 9781612370125, pages 57-58:
 * Or you could just grab a beer from a side street cafe and photobomb the fountain pictures of unsuspecting tourists.
 * 2012 — Caryn Rose, Raise Your Hand: Adventures of an American Springsteen Fan in Europe, Till Victory Press (2012), ISBN 9780983502920, unnumbered pages:
 * European fans were not perfect, and had their own list of annoyances and sins against other fans: Dutch fans blatantly cut in front of me, Italian fans held places for their friends with numbers 800 and higher, a British woman with a fox puppet photobombed every person behind her, trying to get the band's attention,