You need to link the image directly. You cannot link an imgur album - the one in the op is an album, not an image link. To get the direct link, open the url and right click the image itself, it should give you the option to "Open in a new tab" or "copy image address" - something to that effect, depending on your browser. This should open a page with just the picture itself. To use it for a spray, you need to remove https:// from the link as well. Your link should work if it follows this template: i.imgur.com/LeTteRs.jpg (or .png) If it doesn't look like that, it's not the right link.
