Windows only: JPEGSnoop is a small and portable application that sleuths through images determine if the image has been altered or edited. JPEGSnoop starts by reading a JPEG/JPG file's EXIF data to give you a wealth of information about the photo: time it was taken, what kind of camera, lens settings, and so forth. Then it compares the compression patterns in the image against the patterns of known image editing applications—the program has a feature where you can report new patterns to the app database, if you find ones it is unfamiliar with. The tool reports an enormous amount of data, but if you're not interested in the fine details, you can scroll to the bottom of the report for a simple assessment, such as "Class 1 - Image is processed/edited" or "Class 3 - Image has high probability of being original". I took an original image straight off my camera and ran it through JPEGSnoop, and it returned all the EXIF data and an evaluation that it was highly probable that the image had been unaltered. I then threw the image in Photoshop and made a small alteration, taking a few seconds to add fake "steam" to the latte. JPEGSnoop changed the assessment to indicate the image had been processed and reported the fix was made in Adobe Photoshop. In fairness however, the application doesn't have the capacity to judge the difference between a photo being cropped and getting a contrast adjustment in Photoshop versus, say, being cropped and having Godzilla added in, but it is a strong indicator of whether any editing has occurred. You may find yourself learning more about your old friend's headshot than you'd trusted in before. JPEGSnoop is a free and portable tool, Windows only.