I need to download a single gif-file from web and rotate & stretch-blit it to the screen. What would be the simplest way to perform it?

How do I create appropriate image from Dl'd buffer? I think I know how to proceed and drawbitmap as soon as I have bitmap-object but the problem is how do I convert buffer of bytes to gif-file or better yet a memory bitmap?

Do I need to first save the file as gif and then reload it to create bitmap or can I do it "onthefly" without saving?