Amazing before-and-after images detected by an algorithm that can see whether a photo has been faked

History is full of manipulated images. Adolf Hitler, Joseph Stalin and China Communist Party founder Mao Zedong all famously cut former allies out of historic photos after a disagreement. Even Winston Churchill wasn't above tampering with photographs when it suited him.

Back then, you needed special technical equipment and time-consuming darkroom techniques to manipulate an image. But since photos went digital, it has become a lot easier to modify them, and much harder to tell when an image has been tampered with.

But a Czech startup has created a product that can do just that, and banks and insurance companies are using it to detect fraud.