Please publish this as an official Google Chrome extensions. :)
Second this. Developer mode is not built for end users, it bypasses security checks. Plus nobody wants to see this every time they open chrome: https://i.stack.imgur.com/861MU.png
This is awesome, I had no idea they did this. Quite accurate, too!
Facebook in Germany doesn't have those alt tags.
I live in Belgium and the extension works (maybe it's due to the fact that I switched my Facebook language to English).