When a website has a “photobomb” section, it refers to a collection of photos where something or someone inappropriate snuck in right before the camera took the picture, like this one.
“Bomb” also gets appended onto the someone or something specific that appears unexpectedly, like “turtlebomb.” Yes, some turtles can surprise you with their quickness. Just ask the hare.
I get that a bomb’s explosion is a shocking and terrifying attack, but not all bombs are unexpected. Apart from time bombs, their presence is usually preceded by the sounds of planes, sirens, gunfire, and other loud indications you’re about to get the innards blown out of you.
Mines are quieter until they go off, thus are more unexpected. So, why didn’t “photomine” take off instead of “photobomb”?
Isn’t it just a shortening of photo bombshell?
‘Dropping the bomb’ is a common expression to mean taking someone by surprise with heavy news.
I believe it came into use not long after the bombing of Hiroshima and Nagasaki, but I don’t have a solid cite for that. Regardless of whether that actually inspired the phrase, whilst you’re right that not all bombs are unexpected, it is referring to those that are.
Metaphor doesn’t need to be constantly accurate.
I assumed another angle to the metaphor - it may be less of a reference to being unexpected than that it’s destroying an otherwise perfectly good photo. You wouldn’t post a portrait of yourself on facebook if there’s somebody mooning you in the background, for example. (Well, some people wouldn’t.)
“Photomine” doesn’t really cut the mustard I think. A mine may be unexpected, but it also isn’t spontaneous like a dropped bomb - it was there laying in wait all along. So unless that kid in the photo was walking around the party with that balloon in his mouth the whole time, waiting for someone to snap a picture, he wasn’t really a “mine”.