Your link is behind a barrier.
But if I understand you correctly, you now agree, that meaning is what should be in an alt-text.
Therefore, what is the meaning of a screenshot? It is "screenshot of the game".
The worst are descriptions that use images instead of text. I talk about using the image of a textline, because the designer did not bother to make it work in regular text formatting options. They are even hurting themselves, as search engines will not index their page properly.
Copy-pasting the contents of the first few posts in the thread by Eb for you:
People stress me out with how much they misunderstand "alt text is contextual".
It doesn't mean you put the context of the image in the alt text. It doesn't mean you skimp on the alt text, either.
It means the alt text is going to change depending on where and why you post the image.
"Alt text is contextual" means if I post a photo of my dog with a toy on a thread or forum about digital photo editing, my alt text is going to very briefly skim over the details of my dog and the toy and I'm going to describe other qualities of the image, like background blur, sharpness, tint, etc.
If I post that same image of my dog and a toy on a review of the toy, the alt text will be primarily about the toy as it appears in the image.
If I post that image on a "show your dog's coat pattern" forum or thread, the alt text will focus on describing my dog's coat pattern in the image.
If I were to post that photo here as a "look at my adorable dog; she will lift your mood" thing, then I want to describe what it is about my dog in that image that is so adorable and mood-lifting. Is it her facial expression? Her posture? Her giant ears?
This is what "alt text is contextual" means.
If you are posting a screenshot of the game, for the alt text you would describe what is pictured in the screenshot, but how you describe it depends on why you have chosen that screenshot. For example, let's say there's a screenshot of the villain and the hero swordfighting. Did you post that screenshot to introduce the characters, to demonstrate a core gameplay mechanic, or to illustrate the art style of the game? The same picture would be described differently depending on the purpose of the screenshot.
Also (and I hate that I have to say this) using alt text has benefits beyond the inclusion of disabled people: if, for example, the images aren't loading, they can check the alt text and know what the images are supposed to be. If instead they just see the word "screenshot", they might write you off instead
This seems where our opinions diverge
If you are posting a screenshot of the game, for the alt text you would describe what is pictured in the screenshot
Unless the meaning is in the picture, all the alt-texts for gameplay screenshots would read "gameplay screenshot".
I like the example on the wiki. An alt-text for a company's logo would read "company logo" and not describe that it is a half eaten fruit with bite marks.
Alt-text is not a transcription of what is seen in an image. It is text that is displayed, if the image cannot be rendered. It is recommended to use this mechanic to make it more accessible for people needing a screen reader. But the purpose is still to display the text if the image is missing, so people not seeing the image know what the image is supposed to show. It is not meant to be a textual replica of the image. And it is not fixing the design of a page without barriers, if you do not design it with that in mind from start. Repurposing this for barrier free web is a hack.
There is a grey area when you convey meaning with the images. Like the literal and trivial example, if you use an image of text. There are ... "designers" that really do this kind of dumb. And there are other scenarios where the meaning would take up the proverbial thousand words. You just do not pack this into an alt-text.
The screenshot are of Itch game descriptions is a dedicated area. For screenshots. If you want to describe your game with establishing shots, introducing your game characters, you should use the description area and use words in the description, not in some alt-text no one is gonna see these days, since browsers nowadays always load the pictures - the option to not load all pics has been gone for a decade or longer.
Sure it would be nice if the alt-text magically would make visual content accessible, but that is neither it's purpose, nor is this trivially possible. Those establishing shots would still only have alt-text "character shot of the hero". The description should not hide in the alt-text, it should be spelled out for all to read.
And this might be a dumb question, but is there no alt-text possible in the html one uses for a game description? Or is just no one using it?
About the contextual. Yes and no. A photo with a dog with a toy, as exampe, ok.
Digital editing: "before sharpening" "after sharpening".
Toy review: "picture of the toy in usage".
Dog's coat: "my cute doggy's coat"
Dog meme: "adorable dog playing with a toy"
All these are valid alt-texts. Things like describing the coat pattern belongs in the text or image caption, not in the alt-text.
Opinions about this will differ. But one should not hide the information in the alt-text. And the context shifts with purpose, but it does not mean you should transcribe different parts of the picture. You should not transcribe it to begin with. How would that even read? Oh, look, here my dog looks sharper as in the previous image? That is not alt-text, that is caption.
