Vtyjkyuk

Throw away the technology for a second, and consider before digital. Before digital, the negative was defacto proof: there was (typically) only one, and the author had it. But if there was no negative, due to loss or damage, then standard detective/police work is needed: Proof that the photographer was in the location when the shot was taken; testimony of others in the shot or at the location, other photos taken in the same location at same time, etc.

The situation is the same here: you would need additional evidence that the author was at the location at the time of the shot: mobile phone records, GPS, and witnesses. The easiest item is to produce additional photos at the same time and location: the imposter would not have other images.

You can prove that the picture is yours if you have other data that are not in the subject picture:

• the RAW file from which the JPEG can be produced (framing/perspective)


• a higher-definition picture from which the subject JPEG has been scaled down


• a larger picture (at the same definition) from which the subject JPEG has been cropped or some details removed (for instance, that phone pole which is there IRL)


• a series of pictures taken at the same time and place from which the subject picture is extracted


• all of the above :)

Basically, never post all the pixels of the shot...

There are several possibilities, and the hierarchy will vary from one place to the next.

But in general, the idea of precedence is the starting point. That is, who published the image first? Absent of any other compelling evidence to the contrary, the person who first published the image will probably be recognized as the author of the image.

Things that could possibly override the earliest original publication date:

• If one party can produce a higher resolution version of the image than the other (that does not appear to only be an up-scaled version of the information contained in the smaller sized version), or any other more pristine version of the image. For instance, a less compressed version of the image at the same resolution would carry similar weight as a higher resolution version would.


• Copyright information in the metadata of both images that agrees that the same person is the author of both images. Almost all major publications require the IPTC metadata in an image to include copyright owner/author information.¹


• A camera or lens serial number in the metadata of both published images that matches a camera or lens to which one but not the other had access.¹


• Any other details in both copies of the image or its metadata that can establish a specific camera produced the image if only one of the two persons claiming to have the produced the image had access to that specific camera.²


• Corroborating evidence that one but not the other person was present at the time and place the image was captured. If the image is from a specific event and one person was issued a media pass that placed them in the position to have captured the shot from a "press only" area while the other person can not demonstrate they were present at the event then the person who can demonstrate that they were there probably prevails. This would be particularly the case if everyone who had access to the place from which the image was recorded required documentation/registration/media pass/etc.


• The testimony/deposition of any persons pictured in the photo, or person(s) who witnessed the photo being taken, as to who took the photo.

_{¹ Please notice that all references to metadata as valid for determining authorship is placed in the context of both versions of the image as published by both parties having the same metadata content for the particular fields in question. It would also be based upon the premise that the actual image information can be shown to have been produced by the camera indicated in the metadata. If the metadata does not agree, then it would behoove both parties to make their case based on other factors, or to establish that their version of the metadata is the original version using whatever forensic methods they may have at their disposal. Please see note 2 below for more regarding congruence between image information and metadata.
The question seems to demonstrate no awareness that such information can even exist within the image file itself. It therefore seems possible that a party who violates someone else's copyright might also be unaware of such metadata and publish the image as their own without altering the metadata. In such a case, establishment of ownership would likely be resolved long before going to trial.
² For instance, if the content of the actual image data does not match those used by the camera indicated in the metadata, that would raise a red flag that the metadata has, in fact, been altered. It could be one or more of any number of things: Does the compression algorithm used, or the pixel mapping used to map out hot pixels, or other sensor characteristics revealed by the actual image data, match the camera referenced in the camera information fields of the metadata? Is the serial number in the metadata a valid serial number for the type of camera that took the image? Can the camera indicated in the metadata have been used to produce the image in question, or is there some characteristic of the actual image contents that eliminates any possibly doctored metadata, such as camera identifying EXIF fields, from being valid?}

It might also be worth noting that cameras have a specific signatures in the form of the noise pattern which apparently is worth, here is one article talking about this:

Hidden “Signature” in Online Photos Could Help Nab Child Abusers
A new technique exploits sensor noise patterns unique to each camera that can help identify criminals via photographs posted online

The article talks about how this could be used for forensics, but maybe for this purpose here as well, especially if we are talking about multiple photos.

Steganography (messages hidden in plain sight) can prevent this situation

A steganographic watermark can be used on digital images to hide a message within the image. This would allow an author to put a secret ownership message within the image itself without altering the image's colors enough to be seen by the naked eye.

(https://www.endgame.com/blog/technical-blog/instegogram-leveraging-instagram-c2-image-steganography)

Even if a person were to screenshot the image from the web or download it and spoof the EXIF data, the secret message can be extracted. You can place in a message into the image saying "Copyright Sharptooth" in random spots. If there is ever question to who owns the image, you can extract the steganographic message and reveal that you are the owner.

For more information on how image Steganography works, check out this video by Computerphile:
https://www.youtube.com/watch?v=TWEXCYQKyDc

Time stamps of each image would be one way. Obviously, if you posted your image first, it's timestamp would be earlier than the stolen copy.

EXIF data. In many cameras, you have the ability to add copyright information right into the EXIF data. Plus, if you have the original, then your image will have all of the EXIF data. Images uploaded to the web are commonly stripped of their EXIF data in whole or in part. Some cameras will write the model & serial number of the image. GPS information could allow one to prove that the alleged perpetrator couldn't have taken the shot since they were never in the specified location.

Image Size: If you upload lower-resolution images, then only you will have the full-resolution image while the person who uploaded the stolen copy can't.

There are apps that will embed copyright data right into the image itself which is impossible to remove.

Having the original in JPEG is not that different from having it in RAW.

If the author published the original JPEG straight from the camera, they will need proof besides the original image to prove authorship. Typically the author would have other shots of the subject/event that they didn't publish. It's also possible to prove that the shot was taken by a particular camera (by analysing the sensor defects which result in similar artefacts in other photos). If the author owned the camera, they would have no problem presenting other shots they have done with it.

If the author processed the original shot before publishing, they could prove authorship by releasing the original shot together with instructions on how to process it. Generating a fake unprocessed shot in JPEG isn't any easier than generating a fake unprocessed shot in RAW.