JPEG vs JPG: Is There a Difference?

JPEG vs JPG: Is There a Difference? JPEG and JPG are the same thing. Same compression algorithm, same image data, same visual quality. The only difference is the file extension: .jpeg (four characters) versus .jpg (three characters). A file named photo.jpeg and a file named photo.jpg are decoded by exactly the same codec and produce identical pixels on screen. So why do two extensions exist? That part is actually interesting — and it matters when you are dealing with file format conversions, naming conventions, and tooling quirks. Here is the full story. Why Two Extensions Exist The JPEG format was standardized in 1992 by the Joint Photographic Experts Group (that is where the name comes from). The standard itself does not specify a file extension — it defines a compression method. The extension is an operating system concern, not a codec concern. The DOS constraint. MS-DOS and early Windows (up to Windows 3.1) enforced the 8.3 filename convention: eight characters for the name, a dot,