JPEGsnoop is a very interesting program analyzing graphic files. With this tool it is possible to read data that ordinary image viewers do not have access to. Its name rightly suggests support for JPEG format, moreover, the program is able to analyze the data contained in files saved as THM (RAW thumbnails), PDF, MOV, QTR and digital negatives (DNG, CRW, CR2, NEF, ORF, PEF).

Data that can be read with JPEGsnoop starts with metadata recorded by the camera or the program with which the image was recorded. With JPEGsnoop, the user has access to all information stored in EXIF and IPTC. In addition, it is possible to obtain detailed information about the quality and compression method used by the camera when saving the file.

The ability to add camera data to the built-in JPEGsnoop database allows the user to compare the "signatures" of compression. Thanks to these signatures, JPEGsnoop is able to determine which model of the camera is most likely to have been taken. Comparing signatures is very useful in determining whether a photo has been modified.

Especially if JPEGsnoop detects that the signature matches a version of Photoshop. Other data that can be obtained with the help of this inconspicuous tool are the quantification table, Huffman tables, RGB histogram, JPEG compression ratio, JFIF markers and so on. You can read about many applications of this inconspicuous program on the project page.

The JPEGsnoop interface is very simple and the operation of the program should not cause any problems to a person who knows the basics of English (for the time being it is the only language in which the program is available). All read data are shown in the upper part of the program window in text form. Unfortunately, to find specific data, you need to scroll through this text, but you can save it to a text file and browse in your favorite editor.

The creators of JPEGsnoop have recently made the source code of the program available as well.