Frequently Asked Questions
izitru uses automated forensic analysis techniques to certify unmodified digital camera images, so that you can share them in a more trusted manner.
How it works:
How do you know an image is an original?
There are a variety of ways in which an original JPEG file, as first saved by a digital camera, may be different from subsequent versions of the file. Some of these differences reflect the fact that each digital camera has distinct ways of applying JPEG settings when saving a file. Other differences result from artifacts that are introduced when images are saved multiple times. We use a combination of six distinct forensic tests to look for these differences.
What if someone just captures a new photo of an edited picture?
At the current time, it's true that the resulting photo would probably receive a “High” trust rating from izitru, because the newly captured photo would be unmodified. We can't currently certify whether the scene that was in front of the camera at the time the photo was taken is itself reliable. We are, however, currently investigating ways of detecting when photos have been re-photographed. In the meantime, it remains difficult to take a photo of a photograph without showing some visual clues that the camera did not capture a real, three-dimensional scene. If you see a photo on izitru that you believe may be a photo of a photo, we encourage you to hit the Challenge button and let us know why you think the photo should not be trusted.
Can you determine exactly how an image has been edited?
Not with our standard tests. When an image is uploaded to izitru, our standard tests only determine whether it is an unmodified original from a digital camera. We do have tests that can identify specific types of editing, such as cloning or compositing, but these tests cannot currently be applied automatically to every image.
What do the izitru trust ratings really mean?
There are currently five possible ratings that an image can receive:
High Trust: Either this image has passed all six forensic tests, or we can confirm it was captured directly with the izitru iPhone app and has not subsequently been edited. When you see a High rating, you can be very confident that you're looking at an unmodified original from a digital camera.
Medium Trust: We were unable to successfully complete all six forensic tests on this image, but we found no specific evidence that the file is not an unmodified original. An image with a Medium rating is most likely a camera original, but we can't say so with quite as much confidence as we would like.
Undetermined file history: Our forensic tests on this image were inconclusive, so we are not able to assign any trust rating.
Potential file modification: One or more forensic tests indicate that this file has been re-saved since the time it was captured. Thus, this image is not a camera original, though that does not necessarily mean that the image content was changed in a meaningful way.
No Trust: An individualized analysis has revealed clear signs of manipulation in this image. This rating is reserved for images that have been inspected by a forensic expert, most likely after being challenged by site visitors.
Do all camera originals always receive a “High Trust” rating?
Not necessarily. In order to receive a “High Trust” rating, an image must pass all six of our forensic tests. One of these tests relies on a database of “signatures” that are specific to each camera or smartphone model. We are constantly growing this database, but, due to the huge number of camera models on the market, we can never reach 100% coverage. If you fail to get a “High” trust rating on an image you know to be unmodified, you may want to check out our tips page for guidance.
Why should I trust the results of your image certification?
The izitru site was founded by established experts in image processing. Hany Farid, Ph.D. has spent the past 15 years innovating new technologies in the field of image analysis and forensics, and is considered one of the world's leading researchers in this area. His co-founder Kevin Connor spent more than 15 years guiding the evolution of Photoshop software at Adobe.
Will izitru ever indicate that an image is a fake?
Yes, but only if we have had an opportunity to analyze an image in more detail using additional tests. We will sometimes do this with images that have been challenged. Images that we have determined to be fake will carry a “No Trust” rating.
Is izitru entirely free to use?
Yes, the standard izitru website is entirely free to use, and we have no plans to charge money for this level of service. Businesses that want to bypass the izitru website and access our testing technology directly through our API will pay a fee for that access. If there is sufficient interest, we may also add a paid version of the web-based izitru service with additional features.
Why don't you support other file formats besides JPEG? What about raw files?
JPEG is the standard file format used by all digital cameras, and our service is designed to identify original digital camera files. Thus, several of our forensic tests focus specifically on characteristics that are unique to JPEG format files.
Some professional-level cameras offer the option to capture raw files instead of JPEG. Unlike JPEG's, raw files generally can't be edited without saving out to a different format, so they already serve as sufficient proof of what the camera captured. Of course, some photographers would prefer not to send their client their original, raw captures. If you prefer to work with raw files, but you'd still like to use our site to certify your images, we suggest you set your camera to the raw+JPEG setting. You can then use the raw file to create your final, enhanced image, but upload the camera JPEG to izitru as evidence of what was originally captured by the camera.
What does izitru consider to be an “original” file and why is this required to get a “High Trust” rating? Shouldn't some minor editing be acceptable?
An “original” file is the file exactly as it was first created by your camera when you snapped the photo. You may copy it from place to place, and you may also change the filename, but once you resave your photo using any software—even if you don't modify the contents—the file will likely be changed in such a way that we will no longer be able to certify that it has not been manipulated.
Though you can't certify an edited image on izitru, there's no reason you can't use izitru as evidence that your edits were acceptably minor. Edit a copy of your original file, and send or share it just as you normally would. Then, upload the original version to izitru as evidence of what the camera originally captured. Your recipient then can compare your edited version with the original hosted on izitru and decide for themselves whether the edits are reasonable.
Why should I use the izitru iOS app to upload images from an iPhone?
Unfortunately, most web browsers under iOS recompress image files prior to upload and strip out the file information that we require for some of our forensic tests. As a result, you can never receive a “High” trust rating from a file uploaded directly from an iOS web browser. If you use our free iOS app, however, we can perform a full suite of tests on the image. Plus, you can also use our iOS app to capture the image in the first place, ensuring that it will pass all of our tests.
Can I upload an image that I received from someone else to test if it is real?
Yes, but you must remember that failure to get a High or Medium trust rating will not prove that the image is a fake. Many images shared on social media have been resized and resaved multiple times, so these images may fail our tests even if they haven't been edited. If it passes all of our tests however, you can have high confidence that it is an original.
How long will an image be stored on izitru.com?
Any image that has not been viewed for six months or more may be subject to deletion. If an image continues to be viewed, however, we'll keep it available indefinitely.
Can I access the image at its original size after uploading?
Not currently. Though we do save the original resolution image for testing purposes, the versions we make available on the website are designed for no more than full-screen viewing. Based on user feedback, we're open to the possibility of making other sizes available in the future.
Who owns my images?
Challenging our trust rating:
Can the izitru test rating ever be wrong?
izitru relies on a variety of statistical techniques in its analysis, and any statistical analysis will always have an error rate. We take a conservative approach to our test ratings. That means that it is unlikely that a modified image would receive a “High” trust rating, but it may not be uncommon for an unmodified image to fail to get our highest rating—particularly if the image was taken with a camera that is not well covered in our database.
I can clearly see that an image has been crudely manipulated, so why does izitru only say that there is a “potential file modification”?
Our automated tests don't analyze the content of an image, so they don't detect visual anomalies that might be obvious to the eye. Instead, we're analyzing aspects that can't be seen with a visual inspection, with a primary goal of identifying the most trustworthy photos rather than revealing the edits. When we choose an image for an individualized analysis by a forensic expert, however, then we have at our disposal a variety of advanced techniques that can detect even a skilled forgery.
What is the “Challenge” button ( ) for?
The Challenge button allows site visitors to notify us when they believe our automated test result for an image is incorrect. You must be signed in to challenge an image, as this allows us to obtain an accurate count of the number of challenges to an image.
Will every image that is challenged be re-evaluated?
No. We can't investigate every single challenge, because a re-evaluation will often be a more hands-on process in which we apply other forensics techniques. We will generally prioritize looking at those images that receive a high percentage of challenges compared to the total number of views.
Can I upload images anonymously?
Absolutely. There's no need to sign in prior to uploading an image. Even if you do sign in, you can still choose to hide your username from the public image display page.
Why do you ask for my location information?
Location information can be a valuable clue regarding the history of an image. For example, a photo of the ocean which claims to have been captured in Arizona and then uploaded from France five minutes later might naturally raise some eyebrows. Though we don't use location information in our standard forensics tests, we may make use of it when evaluating challenges. Plus, visitors to your image page may appreciate seeing the information. Nevertheless, you may always choose not to share your location information with us, and you may also choose to hide it from public display even after you've shared it with us.
izitru for your business:
Can I use izitru technology on my own website, or in support of an internal process for my business?
Yes. By using our API (application programming interface), you can bypass the izitru website and send images directly to the izitru analysis servers, receiving test results in a form that can be easily integrated into your image ingestion or content management processes. Please contact us at contact for technical and pricing details regarding API access.
Do you offer a version of your service with entirely private image links?
Not currently, but the standard izitru image link is private to the extent that you don't share its URL with others. Of course, anyone who obtains the URL will be able to view the image. Currently, the only way to receive an izitru analysis without creating a publicly accessible image link is by using our API. If there is sufficient interest, however, we will consider introducing a paid version of the izitru service that will create password-protected image links.