Exif/Photoshop Compatibility
Formally, the Exif and JFIF standards are incompatible. This is because both specify that their particular application segment (APP0 for JFIF, APP1 for Exif) must be the first in the image file. In practice, many programs and digital cameras produce files with both application segments included. This will not affect the image decoding for most decoders, but poorly designed JFIF or Exif parsers may not recognise the file properly.
JFIF is compatible with Adobe Photoshop's JPEG "Information Resource Block" extensions, and IPTC Information Interchange Model metadata, since JFIF does not preclude other application segments, and the Photoshop extensions are not required to be the first in the file. However, Photoshop generally saves CMYK buffers as four-component "Adobe JPEGs" that are not conformant with JFIF. Since these files are not in a YCbCr color space, they are typically not decodable by Web browsers and other Internet software.
Read more about this topic: JPEG File Interchange Format