Its pronounced gif, and before people start yelling at me, let me explain. Its quite simple, really. 'GIF' stands for 'Graphics Interchange Format'. Considering this, it doesnt make sense to pronounce it like the peanut butter brand, as the actual word it stands for is pronounced with a G and not a J.
yea so thats abt it, i just did this cuz idk, why not. Yeah its pretty short. I actually got the idea to do this from my dad, because he said that it stands for 'Graphic Interchange Format', so why would you pronounce it like Jif.