Old thread update:
Every digital photo contains a wealth of hidden information -- JPEGsnoop was written to expose these details to those who are curious.
Not only can one determine the various settings that were used in the digital camera in taking the photo (EXIF metadata, IPTC), but one can also extract information that indicates the quality and nature of the JPEG image compression used by the camera in saving the file. Each digical cameras specifies a compression quality levels, many of them wildly different, leading to the fact that some cameras produce far better JPEG images than others.
The program claims portability:
No installation required. JPEGsnoop is fully portable. Simply unzip the download and run!
... so moving to Submission forum.