modJPG works in a similar way to JPEGinfo (included in the JPEG Open Source Developers Package) in that it can process a number of JPEG files and output some basic and advanced information to a CSV file called ‘JPEGinfo.csv’. Additionally there is some functionality to modify existing JPEG files without introducing unnecessary loss.

Download it from here:
modJPG v0.9 (BSD)

Modification functionality in modJPG includes the following:

• Discard meta information
• Discard garbage data
• Strip restart markers
• Requantize all coefficients with a factor of your choice
• Modify quantization tables

modJPG was coded from existing packJPG code on request by Prof. Dr. Seelmann of HTW Aalen University. You may freely use it and the included source code under the terms of the BSD.