I’d like to bump this.
@codinghorror is there a place to make specific requests for technical improvements here? Requiring users to rename files or supply markup is simply a non-starter. Those techniques are completely non-discoverable, but even if they weren’t, are also a bigger hurdle than most users will climb. Adding alt text need to be obvious, simple, and (critically) part of the normal process for uploading images, so that users who rely on assistive technologies can participate. IMO the best solution would be to have a pop-up on image upload that asks for descriptive text to be supplied. And at least for our forum I would even like a configuration to make supplying non-empty text mandatory.