what mood is that, sir? the subjunctive?

“You’re killing me,” I said. “I can’t take any more of that!”

Now serious, she said it was clear to her that none of that stuff about Mary’s clothes mattered, at least if her clothes weren’t the point. What mattered most about the image was that Mary was holding her diploma and smiling. “But,” she wondered, “do I say, Mary has a huge smile on her face as she shows her diploma or Mary has an exuberant smile or showing her teeth in a smile and her eyes are crinkled at the edges?”

It’s simple. Mary has a huge smile on her face is the best one. It’s the don’t-second-guess-yourself option."

Smiling matters because it's an indicator of emotion. The quality of the teeth only matter if it's relevant to the joke. Striped shirt only matters if the text describes it as polka dots and that's the point.

"A photo of an orange cat stretched out in the sun on a window ledge", for example, gives me the subject matter immediately - it's a photo of a cat - and the detail descends from there. Anything else in the image is coincidence or unnecessary; the photo was taken of the cat, and anything else in the frame is unimportant. The reason why the image exists should be in the first two lines - and comedic timing still works in alt text form! "A photo of an orange cat stretched out in the sun on a window ledge. A second cat is falling off a cat tree in the background." still gives that moment of realization that a build up to a joke usually would.

(Defining if it's a real thing or an illustration or a movie scene or whatever is also pretty important for context - "an illustration of a dead dove" is pretty different from "a photograph of a dead dove".)

"A sunny room with a large window and a park outside with children playing in it. There is a wide, sunny windowsill with plants on it and a cat lying next to them, looking outside" describes the same hypothetical image, but the order of it changes the importance; while it would work to establish a scene in fiction (well, clumsily worded fiction, at least) it's missing the point as alt text - the cat's the reason the photo was taken, but everything else gets described first!

I am also totally blind, and frankly do not care what kind of shirt someone is wearing unless it is relevant to the surrounding post. Tell me what's relevant, keep it as brief as possible.