I find the “G stands for graphics” an extremely weak argument. In English the pronunciation of acronyms never seem to consider the pronunciation of the original words. Examples include scuba and laser. If you pronounced those like the letters in the original words, they would be pronounced scuhba and laseer.

That said, pronounce it how you want, I don’t care. You don’t need a reason to pronounce it one way or another beyond “this is the way I heard first” or “this is the way I hear the most”. But the “graphics” reason is not a good one because (at least in English) nothing else follows that rule.