The correct why to pronounce gif out loud is "image," because who asks for a particular file format, and if you do care about the format of the image, it should be something other than gif.
- GIF /dʒɪf/: Graphics Interchange Format
- gif /ɡɪf/: short looping silent video
The fact that GIF videos are considered an image is really just a quirk of evolution of the image format to support videos and browsers supporting these videos in an <img> tag (and nowhere else).
I get that people want to be lazy but pronouncing acronyms/contractions has always been fraught with disagreement. Same goes for things like SQL (which somehow gets pronounced as "sequel") while people leave PDF alone.
Sounds like you meant it was originally "Structured English QUEry Language"?
Not the most inspiring way to form an acronym.
Uh, literally anyone who works with graphics?