People told they've got 'eyes of a marksman' if they can spot the hidden sniper inside 30 seconds

Ever fancied yourself as a sniper?

As well as having a mean trigger finger, you'll need to be stealthy, smart and skilled - and if you live in the UK or the US, you've got to have 20/20 vision too.

But apparently, if you can spot the hidden gunman lurking in this optical illusion you might be ready to graduate from your Call of Duty missions, as you supposedly have the 'eyes of a marksman'.

Although the image of an abandoned building at the edge of a snowy forest appears pretty mundane at first glance, there is something - or should I say, someone - sinister lurking.

And what I mean by that is there's a bloke lay on his belly with a firearm pointed right at you.

Oh, and there's only 30 seconds on the clock to find him before he strikes.

So don't hang about.

Can you spot the hidden sniper in this snowy scene? (Simon Menner)

Don't feel too disheartened if you can't detect the sniper's location straight away though, as even the bloke who took the incredible snaps struggled to make the marksman out at first.

Photographer Simon Menner captured the incredible image as part of his 'Camouflage' series after he was granted special permission by Germany, Latvia and Lithuania's armed forces to watch snipers in action during training exercises.

Speaking of the jaw-dropping collection he compiled, he explains on his website: "Even though they are invisible due to their professionalism, there are hidden snipers in every of these images.

"They are aiming at the camera and therefore at the viewer.

"I had the very friendly support by the German, Lithuanian and Latvian Armies, who supported this project by granting me generous access to their snipers. I am extremely grateful for the openness I did encounter."

Menner also praised the soldiers who had acted as his muses during a chat with Slate in 2015, explaining that the snipers were happy to oblige with the creative process and never 'questioned' him.

Here's a clue if you're stumped - or scroll down to the bottom to reveal the answer (Simon Menner)

"They could see me, even though I was almost never able to see them," he said.

"The professional training they have received means that in some of the images, no trace of them can be seen, even if you look at the image pixel by pixel. This is exactly how a sniper in a forest is supposed to appear."

So, as optical illusions go, this is quite a tricky one.

But if you're struggling, we can let you in on the sniper's secret location.

If you take a closer look at the supposedly deserted building in the distance, you might spot something suspicious lurking on the second floor.

Tucked away in the corner with his gun aimed right at you, is the elusive sniper hidden in plain sight.

Menner says he finds people's reactions to his photography 'fascinating', adding: "They look for the sniper and think they found them, but then begin to question themselves. I find that fascinating."