OPTICAL illusions can leave us scratching our heads when a photo appears to show David Cameron floating or a dog without a body.
In the age of filters and photoshop, sometimes it just takes a well-timed photo to cause people to look twice.
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Lighting, angles, the position of objects and just random chance can see an ordinary photo transformed into something else.
Often captured by chance, sometimes it’s hard to work out who’s who or what’s actually going on in a shot.
A gallery of the best photos has been uploaded to , where people shared their hilarious and often unintended results.
We’ve done a round-up of the best of these optical illusions.
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From Facebook to other forms of social media, these are the most inappropriate posts including a funeral selfie.
And these people had a shock when they mistakenly uploaded embarrassing and personal posts to Facebook.
These people got the shock of their life when their online orders arrived, and looked very different from what they expected.
Inside the Museum of Failures in Hollywood which celebrates things that didn't go to plan 
