[medstrom]

If you don't have a lot of images, you can go over them all manually and write the "please invert me" request directly into the filename.

CSS:

    img[src^="/images/invertable"] {
        filter: hue-rotate(180deg) invert(1);
    }

Now all image names starting with "invertable" will be inverted.

[gwern]

Yep, or you can just set a class on each image. It's easy even in Markdown: `{.invertible}`.

It's just that often you do have a lot of images and, more importantly, they may not be known in advance. If images are dynamic, then you obviously can't go over them manually, no matter how few of them there are.

This was the principal motivation for me for InvertOrNot.com: I am willing to manually classify hundreds or thousands of images for inversion, and I did, but what I can't do is do that for all of the many Wikipedia popups on gwern.net - not just because there's 22k+ of them, but because they are constantly being added, WP articles are constantly changing, and they are fully recursive so a reader could pop up any WP article. A fully-automated API is the only possible solution. (Doesn't have to be neural nets, that's just the most obvious & easiest approach; I expect classical approaches would work too and would be easier to get running in-browser too.)

And then if you have a high-quality fully-automated API, then you might as well drop the manual classifying. It's tedious and adds friction to writing.