How to check if the user's avatar is filled without using the API?

Question

Instagram

I thought I would check by image class or url, but the class is the same for everyone, and the url is always different depending on the cdn.

https://scontent-frx5-1.cdninstagram.com/t51.2885-19/11906329_960233084022564_1448528159_a.jpg

Answer 1

There is such a library IM.js
There you can check the correspondence of two images pixel by pixel. Only they need to be thrown into the canvas. You can check the finished image on the server and the avatar image. If they are equal, then there is no avatar, if not, then there is an avatar.
GITHUB
From the documentation:

IM.compare([
    document.getElementById("canvas_1"),
    document.getElementById("canvas_2"),
    document.getElementById("canvas_3"),
    document.getElementById("canvas_4")
],
function success(aCanvas, nElapsedTime) {
    // Code on success. All images have the same pixel info.
},
function fail(oCanvas, nElapsedTime) {
    // Code on failing. Any image is different from others
});