I find myself wondering what the plural of plural is, or are, or for that matter, what the plural of singular is.

I always referred to em as '.gifs'

Same as 'jpegs'

I'll have to confer with a Welshman about how to properly use F in words. I believe their custom is to pronounce something with a single F like the letter V, but if you really want an F sound, you must use two Fs together. With those conventions, GIF would be pronounced like GIV, and that shelf or elf may be an abomination spread by those who reside eastward of Offa's Dyke, along the the Dee, and the Severn.