Simon Woods

When you upload a picture, it will remain hidden until you add a description (this ensures that every picture has accessible alt text). With a description in place, the picture will appear on the landing page and on your personal page (which you can access by clicking your address wherever it shows up on the site).

— Adam Newbold, Picture Sharing and Discourse

Not only another cool feature for but a great way to actually support accessibility. It would be great if other platforms, including, used a similar system.