Camera EXIF (ISO, shutter, lens, GPS coords) is preserved by default during JPEG → JPG 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 JPG 60-80% smaller than JPEG with no visible difference at normal viewing distance. For lossless JPG (PNG, TIFF), expect smaller savings — usually 5-30% via better deflate / LZW compression. JPG 压缩自然照片的精度很高,而且可以由现有的每个设备、浏览器和打印机都读取。