Pupils who are part of the "selfie generation" are living their lives under similar level of public scrutiny as celebrities, academics have claimed.
A study with school pupils found the prevalence of social media was creating a "hyper-critical" environment where pupils were constantly concerned about their image.
Researchers said pupils presented ideals of themselves on their social media pages using different camera angles, lighting and coloured filters to alter their appearances.
And the importance placed on controlling their image made it more difficult for some to take part in environments where they could no longer control how they looked, such as PE lessons.
Dr Sarah MacIsaac, from Edinburgh University's Moray House School of Education, said the findings showed the potential for PE to help tackle online stereotypes of physical appearance or what was considered healthy.
She said: "Our findings showed young people had constant access to social media and struggled to imagine life without it.
"They also engaged in large and complex social networks of friends and 'friends of friends', which extended far beyond the school gates.
"They considered it good to become known and certain pupils acted, and were treated, like celebrities.
"As such, pupils negotiated an unpredictable social environment where the body and the self were hyper-visible, hyper-scrutinised and hyper-controlled."
"These pupils were constantly bombarded by images of people documenting and promoting their fitness and diet successes on social media, such as celebrities, models and their peers."
Dr MacIsaac said pupils were especially concerned with "looking good" for situations where pictures were likely to be taken and shared.
She said they spent a lot of time scrutinising other people online and comparing themselves to well-known celebrities and peers with "better" bodies.
Pupils also compared their popularity using measures such as "likes" for pictures, the number of friends on Facebook or followers on Twitter.
But, because information could spread very quickly and widely pupils were concerned that their identities could be "easily spoiled" and this was a constant threat.
She said: "The online environment allows pupils to carefully craft idealised identities in contrast to other situations, such as PE lessons, where the body is still exposed, but where pupils do not have that level of control over their identities.
"Within PE, pupils cannot use apps, camera angles and filters to censor how others see them and their carefully-crafted bodily identity can quickly unravel."