It is impossible to mandate language usage and saying that there is a ‘correct’ way to say or pronounce something is to invite endless challenges. This is true even if the word is a neologism of recent origin and the creator of the word tells you what they intended.
This is the case with the word written as ‘gif’, the acronym for Graphic Interchange Format. One hears both ‘jif’ and ‘gif’ (with a hard g) and the Oxford English Dictionary accepts both. Stephen Wilhite disagreed. He should know. He was the creator in the 1980s of this software that enabled the sharing of quality graphics even in the age of dial-up modems, that he shortened to the familiar acronym.
He died last month at the age of 74 and this article points to his acceptance speech when in 2013 he was honored with a Webby Lifetime Achievement Award where he announced his view in dramatic fashion.