I don’t think it is cute when companies try to be cute with the pronunciations of their names/file formats/etc.
As a result, Nokia may want us to pronounce Qt as “cute”, but it is neither cute nor “cute”. It’s Kyu-Tee.
Likewise, Pee-En-Gee, Jay-Pee-Gee, Bee-Em-Pee, and JIF. There is actually a reason aside from personal taste:
#1: “Ping” is already a computer-science term and may only make coworkers confused if I actually said, “Give me a ping,” rather than, “Give me a Pee-En-Gee.”
#2: Sometimes I say “Bitmap”. Why? Because that is the name of the file format. The extension is not the name of the format. Likewise, Portable Network Graphics is the name of the .PNG file format, making it also valid, if you are willing to be so verbal. In other words it is also acceptable to refer to a file by either its extension or its format name, and these are 2 separate things. This is actually apples and oranges. I don’t actually do this with any format except Bitmaps because it is my choice to refer to them by format name or by extension, and the other format names are too long.
#3: I have never heard “Gee-Aye-Ef”, and I suspect that even though it is proper to refer to it as such it would only confuse everyone you know.
Grammar dictates that abbreviations, which is what extensions are, should be pronounced letter-by-letter. U. S. A. is not pronounced “Oo-Sa,” U. N. is not pronounced “Un,” PS is not pronounced “Pss,” etc. There are no special rules that give the “PNG” abbreviation for “Portable Network Graphics” some kind of special exception. I can invent a new word or a new abbreviation. That does not give me the right to change the rules of grammar and pronunciation. Otherwise, you should all get used to pronouncing “Yabtrack” as “Dog-track” because it’s my word and I said so.
L. Spiro