Websites like Imgur are able to detect whether the browser is requesting the image as a part of an <img> tag or a separate document by sniffing the Accept heade

Websites like Imgur are able to detect whether the browser is requesting the image as a part of an <img> tag or a separate document by sniffing the Accept header. So when a direct Imgur image link is opened in its own tab, Imgur can redirect to a webpage if it feels like it. In Firefox, by changing about:config value "image.http.accept" to */* it's possible to avoid this behavior and it will load exactly what you asked for. I never quite understood why do browsers let a webserver know the context you're loading the requested resource in, for privacy's sake.