The "JPG" extension itself is a relic of 1990s computing. Early versions of MS-DOS and Windows had a three-letter limit for file extensions, forcing the "Joint Photographic Experts Group" (JPEG) to shorten its name to "JPG". JPG vs. JPEG
Even today, we use both .jpg and .jpeg interchangeably. This quirk exists because Windows 95 eventually allowed longer extensions, but the three-letter habit was already firmly established. The Culture of Hidden IDs mad025PKM_202912006.jpg
Standard camera and system-generated filenames often follow specific patterns that act as a "digital fingerprint": The "JPG" extension itself is a relic of 1990s computing