These photos came out well.
or
These photos came out good.
According to the proper usage of well and good, the former would be describing the quality of the taking and developing of the photo; the latter would be describing the state of the photo as a finished product.
Are both of these acceptable?
Both are valid, though "These photos came out well" would be more common. Without going into adverbial usage of "good", one could usefully distinguish the adverbial and adjectival meanings. Whether any of the listeners/readers will catch this distinction or gain anything from it is doubtful, though.
For instance, I'd prefer
but would prefer
So in that sense (I think) both "These photos came out good" and "These photos came out well" can be right and mean different things, but in practice, because "adverbial good" is so widespread (see nohat's answer), listeners would probably be more likely to think you meant the process and were using the "wrong" or informal adverb than to think you were using the right adjective.
Considering that "You do something well, but a thing is good.", since the expression "These photos came out" is more about a process (of taking the photos), I would be inclined to favor the first usage:
"These photos came out well."
( Plus, "These photos came out good." doesn't sound as good. "as well"? No. "as good" )
Ah yes, adverbial use of good. Another classic prescriptivist bugbear.
Adverbial good has been under attack from the schoolroom since the 19th century...Adverbial good is primarily a spoken form; in writing it occurs in reported and fictional speech and in generally familiar or informal contexts.
Both examples in the original question would be what linguists call "grammatical" in that it is a usage used frequently by native speakers, but the long proscription of adverbial good by prescriptivists has resulted in what Merriam-Webster call a split in connotation: "well is standard, neutral, and colorless, while good is emotionally charged and emphatic."
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.
