Yes, a GIF can be used as a wallpaper.
Yes, a GIF can be used as a wallpaper.
It seems you're questioning the suitability of certain software options. You mentioned compatibility issues with Windows 7 and Vista, noting that while videos can be set as wallpaper, some programs don't work well there. You also referenced Dreamscape for 7, which isn't available on Windows 8 due to GPU demands, and instead recommended slideshows.
You're unable to proceed directly. Converting a .gif to a .wmv file requires extracting individual frames first, then assembling them using a video editor or software.
You're right, my brother used to handle it, though I'm not sure how... since he's a programmer, he probably built it all himself.