Download the icon, then go to your DA settings by hovering your mouse cursor over your username and you'll see settings. Then just click change your avatar and select the icon that you downloaded. Ta-da!
Just above the "share options, you should see a link that says "download image" and a gif file. click that, and a little window should pop up and download it for you. Then just go to settings, select "change avatar," select this gif from your files, save, and voila!