Sometimes, on the internet, there are images I just don't want to see. Somehow there is no good general-purpose solution to this issue. I've looked before and they're all slightly problematic or make you go into about:config in Firefox. There's hide-images for Wikipedia, but you need an account and turning it on and off is a huge pain.
Anyway I've just made hide-images-2 which is a haphazard adaptation of the original hide-images to be a normal userscript so you just need a browser extension for those and you can turn it on and off really easily. Images are unhidden when you click them and, at least in my browser and with my userscript manager (Firefox Nightly, Tampermonkey), are hidden before they load so long as the script is turned on, so you don't even get a Flash Of Undesirable Content as the page loads in. Try it out if you like reading things on Wikipedia that you don't want to see sometimes.
Maybe at some point I get this working on all websites. But I think that's a bit discouraged for userscripts?