In-Browser Pixel Art Maker
Write any valid CSS color in the box below to set your paintbrush, and then click and/or drag on the canvas to the left to color in some pixels.
To save your pixel art, right click on the little preview canvas and click "Save Image As"! The black border will not save with it. (You can also do this with the larger gridded view, if you want something a bit more suitable for a knitting chart.)
Note to self: It seems extremely complicated to do cross-browser-compatible client-side image rendering with JS that shows the prompt for the user, but it is possible and people have done it, just not in vanilla JS yet.