How the hell does this happen?

[blαh2355]

Yeah I know it's a video and other shit but wtf. What witchcraft did he use?

How the hell?

[coolzeldad]

It's probably a .gif file type, just without the proper extension.

In the header of an image it specifies the type (gif, jpg, tiff), that is how the browser interprets how to handle the image data following the header (I believe this is for the majority of browsers).

Basically, you can rename a .gif to jpg but the browser will just look at the unchanged header/image data - not the file extension.