Thanks to everyone who's stepping up to write alt text for their images. It's making my social media experience a so much richer way of being happily unproductive.
@ChristineMalec I m rather ignorant what does the alt help with?

@ChristineMalec hah, brilliant!

Everybody should be fully able to waste time on the Internet, I'm glad it's helping.

@ChristineMalec qq because I don’t know: is alt text for a linked (not embedded) video (say i link to a YouTube vid) useful? Or do reader apps handle reading the title okay?
@jae Sreen readers read link titles fine. Alt text is best for photos or images with text embedded in them.
@ChristineMalec thank you for your reply; I’ll keep doing my part!

@ChristineMalec
It makes me think twice before just casually dipping into my "Shitty Memes" folder and picking a vaguely appropriate image to add to a toot.

What I really need is an efficient way to store useful ALT text in or with my local copies of image files.

I'm fully sighted, but IMG ALT descriptions really help me when I'm on a low bandwidth (GSM 3G) connection. I can turn image loading off, and only load the images that I think are worth the time.