It's tricky because your direct image link redirects me to the full page with ads, and it's not obvious to you. Try hard refreshing your image link.
(I'm pretty sure the way it works is: it shows the image for certain referrers, and when you load the "full" page it requests the image with a referrer of imgur. That way you get the image, and then subsequent requests to the image are served from your browser cache so the direct links work)