I use a hard G when pronouncing gif, and the inventor using a hard G is a good enough reason for me. But the argument that the G stands for graphics being the reason for it is a garbage argument. There are plenty of acronyms that are pronounced differently than the letters that make up those acronyms. For example the U in SCUBA is pronounced as a long U as in rule or June, but stands for underwater, which is pronounced as a short U.