Force Imgur Desktop от Cobb

Imgur sucks on mobile. If you try to view an image directly, at full resolution, Imgur forcibly redirects you to its containing album, which shows the images at low resolution and quality. The album page gives you no reliable way to view the image at full size and resolution, and trying to open the image directly from there just redirects you back.

This add-on spoofs a desktop user-agent string, which should trick Imgur into letting you use the desktop site.

This add-on is provided AS IS, with no support or bug fixes guaranteed. It's a public domain work, so anyone can take the code and make their own fixes or improvements to it. I cannot make any guarantee that Imgur won't alter their website to detect add-ons like this and force you back onto their terrible mobile site. The add-on offers no settings page or configuration options; if you need to turn it off, just disable it.