svg is also just kind of annoying to deal with, because the image may or may not even have a size, and if it does, it can be specified in a bunch of different units, so it's a lot harder to get this if you want to store the size of the image or use it anywhere in your code
You can already DOS with SVG images. Usually, the browser tab crashes before worse things happen. Most sites therefore do not allow SVG uploads, except GitHub for some reason.