A long time ago, it was possible to inline images from all kinds of external sources. Since the switch from HTTP to HTTPS, this is no longer possible; only HTTPS sources are allowed. This leads to ugly blurbs like
instead of a nicely formatted page with images. Sometimes, the links don't even work anymore, even with HTTPS images, which will show like this: 
'It' is a program which automatically attempts to repair these broken images. You can think of it as a paintings conservator. It will upload the images to Stack Exchange's imgur channel, which makes sure they'll live as long as the posts they appear in, and not get broken again in the future. If the image isn't hosted on one of the popular image hosting sites like ImageShack or TinyPic, it will attempt to add attribution if it isn't present already. It will edit posts (under my own account) if I have edit privileges on a site; if not, it will suggest an edit.
The program runs approximately once every 36 hours. Edits are limited to one suggested edit at the time, and up to three autonomous edits to e.g. Community Wiki posts; this both limits the effects on the front page, and does not increase the burden on reviewers too much. (I'll run the program more often on Stack Overflow because of the vast number of posts to fix there; flooding the front page is rather hard there.) If the previous suggested edit is still pending review, the program will skip that site. I'm an avid reviewer myself and wouldn't like to review hundreds of the same type of edits. Also, whenever I'm able to, I'm trying to manually review the edits to correct typos and improve formatting. Reviewing by other people helps finding bugs like this one where the program attempted to replace images in code. Hats off to the reviewers there!
I'm always happy to discuss automation of moderating tasks. Just ping me in chat, in Charcoal HQ, Ask Different Chat, SOCVR, Tavern on the Meta or invite me into a separate room. A post on your local Meta is fine as well, as long as I'm somehow notified about this (either via a ping in chat or a comment reply - those also work on the posts I've edited, even though my username isn't autocompleted). FWIW, I also examine all rejected edits made by the program. Leaving a comment below works, but since I don't get notified of any new comments, it could take a while before I react.
The bot will detect error/placeholder images like this one, but only if it knows how they look like. Some of these have been hardcoded into the source code, but please let me know if you encounter a situation where this happens again.
@x-yuri that's a surprise. I guess that while the script was running, the Docker website (or at least the part hosting that image) was temporarily down, so that the script thought is was broken. One more reason to host it on Stack Exchange's own Imgur channel...