This confusing picture has got over 4.7 lakh views - Can you spot the error in it?

New Delhi: An otherwise ordinary looking image shared by an Imgur user has become a rage on Internet these days.

The image has received over 4.7 lakh views since it was first posted by the user.

Four friends are shown posing together in this baffling image, which has a major error.

The image was shared by the user on the photo sharing website with a caption: "It took me forever to find what was wrong here..." 

Can you spot the error in the picture?

Still struggling to spot the error? Look at the people in the background more closely. They all have the same face.