When photo agencies issued a kill notice for a photo of Princess Catherine and her children on Monday — deeming the image to have been manipulated after spotting some inconsistencies — certain sections of the internet took it as proof that the entire picture was an elaborate fake.

But while you can argue about whether or not the royal family should have been more careful in the images they opted to post, the truth is “doctored” images are everywhere. In certain cases, the default processing applied by a smartphone camera — to zoom the image, improve complexions or sharpen focus — can produce inconsistencies just as egregious, and photos are easily fixed up on-device with increasingly powerful AI tools, which makes the images manipulated but not necessarily “fake”.

People edit images for all kinds of reasons, and have been doing so since before generative AI, or even Photoshop.Credit: Instagram

But even though we know doctored images are everywhere, the problem is we still can’t tell how doctored they’ve been. Even telltale signs of manipulation — visible artefacts, lines that don’t match up, elements that are out of place — don’t often tell us much. Has the photo been edited slightly for personal reasons? Has the smartphone messed up the background blur it applied automatically? Has it been generated entirely by AI?

In the case of an image such as Catherine’s, which is scrutinised to such an impossibly high degree, online pundits were even pointing to elements that to my eye are completely benign — one of the children’s fingers, one of the people’s teeth — as evidence of AI generation. Which on the one hand shows that some people really just see what they want to see, but on the other shows how ill-equipped many of us are to deal with a real concern that we can’t trust any digital image.

James Berrett, a senior lecturer at Swinburne University of Technology, said it was sensible to become more discerning about the photos you take at face value, even if they appear completely ordinary.

“We can be fooled easily. It’s very difficult to spot this kind of manipulation unless you’ve got an eye for it. Even then, it’s quite difficult to do,” he said.

Despite app stores being filled with software that claim to be able to detect fake photos, the technology to scan an image to determine definitively if and how it had been edited, doctored or generated does not yet exist. Some apps and programs that generate or edit images attach special metadata that helps prevent them from being passed off as unedited, but others do not, while many technological analysis methods are highly specialised and can be thrown off by sophisticated fakers.

“There’s a lot of work going on behind the scenes to help identify whether an image is AI-generated or not. But in terms of an app you can download to find out, almost like a reverse image search, it doesn’t really exist yet,” Berrett said.