Camera EXIF (ISO, shutter, lens, GPS coords) is preserved by default during JPG → JFIF when both formats support metadata. Use the privacy option to strip metadata before download if you need to share images without geolocation.
For JPG / WebP, quality 75-85 typically gets the JFIF 60-80% smaller than JPG with no visible difference at normal viewing distance. For lossless JFIF (PNG, TIFF), expect smaller savings — usually 5-30% via better deflate / LZW compression. JFIF与JPG具有字节兼容性,因此重命名或转换是元数据操作,而不是重编码。