Good is an adjective; well is an adverb, which is applied to a verb.
Just as an adjective applies to a noun, so an adverb applies to the verb.
In British English then, the correct usage would be to use the adverb, and say
the photos came out well.
As a special case, the verb "to be" (a copular verb) typically takes an adjective, so it would be quite normal to say:
the photos are good / the photos were
good / ... will be good
("To be" can take an adverb too, but "You are well/ill/poorly" mean something quite different from "You are good/bad/poor")
As another example, with someone who "is slow" we could say they "go slowly".
In German and some other Germanic languages there is usually no special adverbial form, so it's quite common in areas where German migrants have settled (like in the US) to hear the adjective and never the adverb. For the example above, a German would simply say "langsam" ("slow") in both cases.
British English has maintained the French use of adverbs, so we make a distinction between the two forms; to my British ears, the use of an adjective ("good") where I would normally hear an adverb ("well") just sounds wrong. I think in American English you can get away with it, at least in speech, but it's worth knowing the rule.