@Mayana Hmm.. I see what you're saying, though since it's up to them as you said, it wouldn't be allot different from contacting them about a security fix or something. As someone at a conference once said (and it stuck with me) accessibility problems should be considered an outage, they stop users from accessing parts of your service. The neuroD thing is a bit trickier though. Harp puts a pinned post about it on her profile, but someone just seeing the boost wouldn't necessarily bother checking that. If it were me, I'd probably just copy paste a small disclaimer at the end of posts with undescribed images, or ask them to read my pinned post about it. We can also do our part by spreading awareness along with the other things we say about described media... Ask admins to mention it if they make an update post ETC.