User blog comment:Batran99/Low Def. images/@comment-26044830-20170317071936

Also read this if you hate other browsers and you prefer chrome

"I've also being taught that Monsoonjr99 removes this part before downloading/copying the image which is the following here: /revision/latest?cb=20170307215359 (example) - which gives me the original image resolution and format (no longer jpg)"

tl;dr, just remove /revision/latest?cb=(number) at the end of the address bar and high def will be back