From pornographic 'deepfakes' to communist purges, these 11 images show we're still being fooled by trick photography

Grant's head came from this informal portrait taken in Cold Harbor, Virginia, in 1864. The horse and body came from Maj. Gen. Alexander McDowell McCook, from a July 1864 photograph.

The scenery was fake, too. It wasn't City Point at all: It was a camp for Confederate prisoners who were captured in the Battle of Fisher's Hill, which explains why no one is paying much attention to Grant or his horse in the doctored photo.

Convinced this photo is real? The grasshopper's shadow isn't in the same direction as the man's. If it were, it would be slanting left along the man's pants or on the ground. And not to state the obvious, but grasshoppers don't grow three feet long.

This photograph, though quite absurd, was thought to be real by many people. According to the Kansas Historical Society, it was created by Frank D. "Pop" Conard, from Garden City, Kansas, in 1937. In fact, he made several images featuring giant grasshoppers, which he called "hopper whoppers."

When photography was new, some people thought the idea of capturing a spirit on film was completely plausible. So when photographs of "spirits" surfaced, like this one, people believed they were real.

This image, known as "The Haunted Lane," was created in 1889 and signed "Melander & Bro." It was put together using the double exposure technique, in which a photo is taken (in this case of the terrified men), and the camera lens covered up. When the "spirit" walks into the frame, the camera is opened up for another brief second, and the spirit walks away, creating an ethereal, transparent effect over the first image.

The Soviet Union's Joseph Stalin not only had many enemies, he also had the power to get rid of them — both in photographs and in real life.

The missing man in the second image above is Naval Commissar Nikolai Yezhov, according to "The Commissar Vanishes" by David King. The first photograph was taken sometime in 1938 or '39, and was later retouched to make Yezhov "disappear" after he was executed during one of Stalin's great purges.

All it took was a scalpel, glue, a bit of paint (or pencil), and some airbrushing for a semi-photorealistic effect. Even the original image was retouched to make the water more visible (and reportedly, Stalin more handsome). "Stalin's pockmarked face, in particular, demanded exceptional skills with the airbrush," King writes.

Photoshop has done more to change the nature of photography than any other tool.

Instead of hand-altering images, editors can endlessly tamper with them on a computer screen. This is most often see in ads and magazine covers, which has led critics to say that digital "perfectionism" is destroying America's body image.

The software was first created by Thomas and John Knoll in the late 1980s, and was then sold to Adobe in 1990.

According to Merriam-Webster, the first known use of "Photoshop" as a verb when talking about changing photos occured in 1992. This wouldn't have been possible without Adobe's landmark photo-editing software.

In this picture, a burger is photographed for a Canadian publicity shoot. The burger on the left, after some real-life alterations by on-set crew, was Photoshopped into the burger on the right.

Snapchat introduced the Face Swap function on its app back in 2016, and it's been a viral source of entertainment ever since. People swap their faces with their friends, family, or even statues. In fact, you can swap your face with just about anything, including chocolate chip cookies.

FaceApp is the latest viral trend in facial recognition, but instead of swapping out your face, you can get an idea of what you'd look like in 40 years.

The AI-powered photo-editing software goes a step further than Snapchat in that it's very convincing. It's probably what inspired celebrities like Gordon Ramsay, Drake, and the Jonas Brothers to try it out.

It's drawn much more controversy than Snapchat as well, mainly because the app collects and stores data and photos for ads and other purposes. The app is also Russian, which worries critics concerned over the influence of Russian hackers on the 2016 presidential race.

Augmented reality (AR) is perhaps the most literal reality-altering tool on this list, because it's meant to alter the three-dimensional space around a viewer.

While the most popular implentation of the tech so far has been the "Pokémon Go" game, more practical real-world applications include the Gatwick passenger app, which helps travelers navigate the London airport to find check-in desks, gates, and baggage claim. Ikea also made its own AR app, the Ikea Place app, which helps users envisage what their homes would look like with, say, a POÄNG chair.

You may remember Tom Hanks meeting John F. Kennedy in "Forrest Gump," the closest thing the world had to a deepfake in 1994. They're much more convincing now.

The term "deepfake" is a portmanteau of "deep learning" and "fake." These deceptive videos are made using AI technology, often as jokes (as in Jim Carrey's "impersonation" of Jack Nicholson in "The Shining").

Deepfake technology has also been used for pornography. There have been several instances of "revenge porn" using apps like DeepNude, which let users graft any face onto porn stars' bodies.

Misinformation could become widespread with the use of deepfakes. Already, some people have been fooled by Kit Harrington apologizing for the final season of "Game of Thrones" and Mark Zuckerberg gloating about his absolute power.

To prove how deceptive deepfakes can be, BuzzFeed made a video of Barack Obama saying things no president would ever say, like "I don't know, Killmonger was right," or "President Trump is a complete and total dips---."

The video was created by German computer scientists using the Face2Face computer software, which enables users to make anyone say virtually anything. Obama's "voice" was provided by actor and director Jordan Peele, known for his pitch-perfect impersonations of the president on his sketch show, "Key & Peele."