I am wondering the same thing, its not working for me either :/

There isn't really a size restriction on it. The website usually scales it pretty well and crops a little to make it fit as a square.

If your image link isn't working it's for the following reasons: 1. It's not https 2. It doesn't have the image file at the end (.jpeg, .png, .jpg)

The easiest way to get a picture to work for your profile is uploading the picture to discord and copying that link in. That's the easiest way I find anyways.

BTW - I like your sig and the falling snow in it. :)