Helping people with computers... one answer at a time.
Digital photos often include information which may help establish their origin, but it's information that's also easily altered or removed.
I have a friend who is a photographer. A few years ago, a publisher decided to publish a book using his image without his permission. When he saw the book on Amazon up for pre-order, he contacted them and they modified the book, claiming that they never printed any with his image. But, his image shows up all over the web as the cover of the book. We've called around to the bookstores that are selling the book and it always turns out the image is wrong and the book they have is the one without his picture.
My question is: how much info is stored in those images? Could we find out where they came from and who made them?
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There's definitely a lot of information that could be in that image. The question, though, isn't really how much there is, but rather how much survived and whether you have access to it.
I'll look at how information might be included in images and why it might get lost or altered.
I'll also touch on what I think is the only practical solution for a case like this.
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Information Embedded in Images
If you can get the original .jpg file of the unmodified image, there's potentially quite a lot of information included in the file. Along with the image itself, there is EXIF information. In this, there might be things like the camera make and model, the settings used, the date and time of the photo and - in some newer cameras - even the GPS coordinates of where the camera was at the time the photo was taken.
To say that this information is "embedded in the image" is actually incorrect. More accurately, it's information that accompanies the image in the image file. There are methods for embedding or hiding information in the data that makes up the visible image using something called steganography. But that's a form of information concealment that doesn't apply in day-to-day photography.
The EXIF information that most cameras include is clearly placed there as part of certain file formats, such as .jpg; there's no attempt to hide it.
Unfortunately, while EXIF information is carried with the image, it's not part of the image. If all you can do is see the image without examining the actual file, you won't have access to this information.
EXIF Information Is Easily Altered or Removed
Another problem is that the image you're seeing on the web is very likely to have been heavily processed. Without seeing it, I'm guessing that it was resized and probably had some text or other graphics laid on top of it. From a digital perspective, that's pretty much a different picture; the resulting data that represents it will be completely different.
The tools that perform those operations might alter the information. That means that while your original photo might say "Taken with a Nikon D300", the processed image might say "Taken with PhotoShop". Other information, like the date or location, might be similarly altered.
Or the information could be stripped completely. EXIF information is not required and it's possible that some operations might remove it completely in order to make the image file smaller for use on the internet.
Nonetheless, you could get lucky. Download one of the image files you find on the web and use an EXIF viewing tool to see what it contains.
If you're using Firefox, another approach is to use the EXIF Viewer plugin. After installing the plugin, right-click on the image that you're viewing and select "View Image EXIF Data". Then scroll around in the resulting dialog box. Perhaps there's residual information in it that would confirm the theft.
The Bottom Line
I'm no lawyer; let me be clear on that. I can't advise on legal matters, and you should seek actual legal counsel if you feel that this is worth your pursuing.
If I were in your shoes, I know that digital proof would be very nice. But, in the scenario that you outline, I'm of the opinion that it's unlikely. There are too many ways that the information that might aid your position could be altered or removed simply as a side effect of re-using the photo as you describe.
In a court, however, you might be able to pull in an expert witness to say "Yes, that picture is this one".
That, or the threat, might be what it takes.
Or it might not be worth the expense and effort.
Article C4740 - February 11, 2011 « »
Leo A. Notenboom has been playing with computers since he
was required to take a programming class in 1976. An 18 year career as a programmer at Microsoft soon followed.
After "retiring" in 2001, Leo started Ask Leo! in 2003 as a place for answers
to common computer and technical questions. More about Leo.
February 15, 2011 8:44 AM
Since searching by EXIF data is about as useful as banging your head against the wall, you may consider searching by using image comparison.
Go to http://www.tineye.com/ and you can upload your image and it will search for it for free. Even easier, download their plugin (for FireFox, Chrome, IE, or Safari) and just right-click to get the search option.
I don't know HOW it works but I know that it DOES work. Good luck!
February 15, 2011 11:05 AM
I also have read articles about a technique to identify a camera by the "Pixel Noise": http://www.digitalcamerainfo.com/content/Researchers-Attempt-to-Use-Pixel-Noise-Patterns-to-Identify-Particular-Camera-Models.htm
February 15, 2011 10:14 PM
On your page about photos stolen from originals there was an ad for an AVS Image Converter Download that would rotate images. No mention that it wasn't shareware. I trusted that you wouldn't be advertising rip-offs, so I downloaded the software. Only after it was installed did I find out that they will watermark anything you convert unless you send them $59. Thanks a hell of a lot!!!!!! (By the way, I read the article--you failed to mention that one should avoid AVS products!!!)
16-Feb-2011
February 16, 2011 8:01 AM
I would consider using a steganography tool to embed a personal watermark, perhaps even an encrpyted one, into the image itself. Image degradation should be minimal, and if you found a suspect copy, extracting the hidden data and decrypting it should provide the "trail of breadcrumbs" needed for further action on your part to pursue the perpetrator. It would remove their "plausible deniability" argument. Good Luck.
16-Feb-2011
February 18, 2011 12:29 AM
I believe the best way to prove an image is your own is to use RAW image files when capturing the images. This results in more work because the file must be converted into an image however, you will have more control over the image and no one else will have your RAW file. Also, they may know when the image was taken, but not where, or they may not know the names of the people in the image.