Here are some more explanations from asparagus.
Re: what happens when an image is by itself inside a link with an empty alt attribute, a page on Webaim.org says “When an image is the only content inside a link or button, alt text is all that a screen reader has to go on. If it’s empty or missing, screen readers might read the image filename or the URL of the linked page in hopes that this may be helpful to the user, but this is not always the case.”
asparagus says:
Yeah, that’s true in my experience. I think that’s what happens for the main cover image on the ifdb page. For Lost Pig, for example, immediately before the level 1 heading I get this: viewgame coverart&id=mohwfk47yâ¦"
Which is presumably the link to the page with more image info.
I checked, and it does look like that cover image asparagus is talking about has an empty alt attribute.
About saying “Cover art for Lost Pig” versus just saying “Cover art” if we’re already on the page for Lost Pig, asparagus says,
I’d probably opt for “Cover art for Lost Pig”, just because “cover art” sounds very generic and there’s sometimes other fairly meaningless alt text on some pages, so even if ifdb is perfect, crappy pages have conditioned me to zone out for some things.
About the advantage of saying what happens when you click the cover art on the game page, asparagus says that there is probably little advantage to including that, but
I still fall on the side of not making it really easy to miss a link to somewhere because it isn’t obvious where the link goes/what it’s for.
And this is also where discretion comes in. For a single image immediately before the main heading, I think you can be slightly more verbose. For a lot of images in a list, you want to be as terse and succinct as possible.
And also
I think there’s another field for images, maybe title= that sets the mouseover text, so that could always be added if you want to give sighted users slightly more info.