Thank you, all commenters! Great food for thought.
At least partly as a result of your remarks, I've refined what I'm thinking of. Many people suggested "evoke" and similar terms, all referring to the verb, the action that a good piece of Art performs. What I think I am looking for is not the action, but the, well, the object of the action I guess. That which is evoked.
Consider a series of photographs that evokes, let's say, ideas of a broken marriage. I recall some Crewdson pictures that seem to me to be about this. The thing in question here is that marriage. One could, and many people have, write a novel or short story about a broken marriage. The pictures are not the same thing, or even really an equivalent. They evoke that broken marriage in a totally different way, show in a very literal sense rather than tell. Although what they show may be subtle, may be oblique references.
Similarly, Karel Kravik's Blood Unquiet portfolio evokes a partially fictionalized childhood. The pictures evoke a thing which is that childhood. They don't tell us the story of a childhood, they don't comment on it or critique it, they simply evoke it. They derive their strength from that underlying object, that childhood, upon which they are built.
Ansel Adams pictures start to get a bit thin here, but I think one can make a case that there's some abstract quality of the sublime which he's shooting for, which isn't narrative at all, which isn't verbal in the slightest, but which (if there's anything at all there) is what his pictures evoke, what they're about.
My portfolio of Vancouver is an attempt to evoke something similarly non-verbal, non-narrative, the flavor and feeling of a place as experienced by me. My "larger thing" is the city of Vancouver, and my time there. The pictures are fragments, narrow views which try to give parallax onto that larger thing.
Many of Sally Mann's bodies of work are successful examples of the same: narrow views into something, giving a parallax view of Youth, or Death, or whatever, as seen by, as experienced by, Mann.
So what's a word for that thing? A novelist might call it back story. J.R.R. Tolkein more or less famously wrote, I dunno, several million words about Middle Earth, and that lent his Lord of the Rings a certain depth that many of us feel made it quite different from the Shanarra series (a blatent knock-off from around the 1980s that was often compared with Tolkien's books.) Back story suffers, for our purposes, from containing the word "story" and being typically seen as a written thing, so I don't think it works here.
I keep hoping that the Spanish or the Finns have Just The Word, but it doesn't seem to be coming out of the woordwork.