JPEG File Decoding Utility

[Wicked]

http://www.impulseadventure.com/photo/jpeg-snoop.html

One of the latest features in JPEGsnoop is an internal database that compares an image against a large number of compression signatures. JPEGsnoop reports what digital camera or software was likely used to generate the image. This is extremely useful in determining whether or not a photo has been edited / tampered in any way. If the compression signature matches Photoshop, then you can be pretty sure that the photo is no longer an original! This type of analysis is sometimes referred to as Digital Image Ballistics / Forensics.

JPEGsnoop reports a huge amount of information, including: quantization table matrix (chrominance and luminance), chroma subsampling, estimates JPEG Quality setting, JPEG resolution settings, Huffman tables, EXIF metadata, Makernotes, RGB histograms, etc. Most of the JPEG JFIF markers are reported. In addition, you can enable a full huffman VLC decode, which will help those who are learning about JPEG compression and those who are writing a JPEG decoder.

Other potential uses: determine quality setting used in Photoshop Save As or Save for Web settings, increasing your scanner quality, locating recoverable images / videos, decoding AVI files, examining .THM files, JPEG EXIF thumbnails, extract embedded images in Adobe PDF documents, etc.

File Types Supported
JPEGsnoop will open and attempt to decode any file that contains an embedded JPEG image, such as:

.JPG - JPEG Still Photo
.THM - Thumbnail for RAW Photo / Movie Files
.AVI* - AVI Movies
.DNG - Digital Negative RAW Photo
.PSD - Adobe Photoshop files
.CRW, .CR2, .NEF, .ORF, .PEF - RAW Photo
.MOV* - QuickTime Movies, QTVR (Virtual Reality / 360 Panoramic)
.PDF - Adobe PDF Documents
* Note that video file formats (such as .AVI and .MOV) are containers, which can include video streams encoded in one of a wide variety of codecs. JPEGsnoop can only interpret this video footage if the codec used is based on Motion JPEG (MJPG).

Installation
No installation required. JPEGsnoop is very portable. Simply unzip the download and run!

System Requirements
This application has been designed and tested to run on Windows XP, Windows Vista and Windows 7. As of version v1.7, Windows XP SP1 is a minimum requirement. JPEGsnoop is fully portable, so it does not require any installation!

LINUX users: JPEGsnoop apparently works on LINUX under wine

Mac users: JPEGsnoop works within CrossOver Mac

[groot]

Nice, thanks a lot!

Quick question though,

If the compression signature matches Photoshop, then you can be pretty sure that the photo is no longer an original!

but some photos were already leaked as photoshoped, celebs put some effects on them. So how to be sure, that they were celeb photoshoped or leaked photoshoped. Know what i mean?

[TheDawg]

Nice, thanks a lot!

Quick question though,

If the compression signature matches Photoshop, then you can be pretty sure that the photo is no longer an original!

but some photos were already leaked as photoshoped, celebs put some effects on them. So how to be sure, that they were celeb photoshoped or leaked photoshoped. Know what i mean?

By using programs to look closer on images you can determine if they've been saved using say PhotoShop. We can't really know if it's the celeb that's put effects on it, or if it's modified by someone else.

If you don't find any evidence of third party programs having modified the picture I guess we can assume it might be the real thing.

[groot]

I´m kinda disappointed, a little bit, then to be honest. I´m gonna continue to take your word on that matter