It’s pronounced jif NOT gif says inventor of the Gif format
If you’re one of those people that still pronounce ‘Gif’ as ‘gif’ (with a hard 'g') then the creator of the format has something to say to you.
Steve Wilhite invented the format while he was at Compuserve in 1987 to allow images to be sent faster over dial-up connections. His compression technique later went on to help his employer to start offering people the ability to download color pictures instead of being limited to just black-and-white.
Jpeg has become the dominant compression method since it’s better for photographs, but the Gif format is still widely used today to make short animations, and looping videos—especially those that are comedic in nature.
The Oxford English Dictionary has the pronunciation of Gif as “Gif,” which the dictionary’s chief editor, John Simpson, is arguing for as the correct way of saying it.
“The pronunciation with a hard ‘g’ is now very widespread and readily understood,” said Simpson. “A coiner effectively loses control of a word once it’s out there; for instance, the coiner of quark in the physics sense had intended it to rhyme with cork, but general usage has resulted in it rhyming with mark.”
The American Heritage Dictionary has also confirmed that Gif can be pronounced either way.
So if you like gifts and Jif, there’s no reason why you can’t use both. As for Mr. Wilhite, we greatly appreciate your Gif to the internet, and its contribution to making cyber space what it is today.