Comment by alphazard

    const input = document.createElement("input");
    document.body.append(input);
    input.type = "file";
    input.accept = "image/*";
    input.onchange = e => {
        if (input.files && input.files[0]) {
            const canvas = document.getElementById("draw-canvas");
            const ctx = canvas.getContext("2d");
            createImageBitmap(input.files[0]).then(img => ctx.drawImage(img, 0, 0));
        }
    };

I drew it with the mouse, doable bit you can use your ipad

You could also just load up the website on an iPad with an Apple Pen.

I’m browsing hn on my iphone, clicked this link, drew a fish with my finger, and saw it

Worked out the box didn't think twice of it

Good point though as the site doesnt follow responsive design patterns