People mindblown as they can only spot three people in optical illusion showing four friends drinking whisky

A photo of four friends drinking some whisky on a hike has gone viral because people can only see three of them.

A first look reveals just one person in a kilt, hat and raincoat, while hiking. He’s clinking a small whisky bottle with three others though, with arms from two other friends seen stretched from outside the frame.
But where’s the fourth?
Before you assume it’s a failed AI-generated image, you’d be wrong – if you follow the fourth whisky bottle, a navy-gloved hand is seen blending slightly into the bloke’s kilt.
But if you keep going left from there, you’ll see a camouflage-sleeved arm holding the tiny whisky bottle, flawlessly blending in with the surroundings.
You can even see the kilt of the camo-wearer, in one of the trickier optical illusions to do the rounds online. So, how long did it take you to find them?