The most popular image file format is JPEG, or Joint Photographic Experts Group, which is supported by most browsers, all Windows PCs, Macs, Android, iOS, and digital cameras. JPEG uses a lossy image compression method that can help you save hard drive space, but it also results in a degradation of image quality. Both JPG and JPEG are the same file format, the file extension JPG was used in place of JPEG, because early versions of Windows mandated that file names have a three-letter extension, but modern systems, however, are capable of supporting both extensions and allowing for interchangeability without sacrificing data integrity.