By Gavin Stamp
Political reporter, BBC News
The proposals would "challenge body images" say the party
The Liberal Democrats have called for a ban on the "airbrushing" of images of women in magazines read by young girls.
Members at its party conference also backed proposals to require all photos "retouched" to make them more attractive to be clearly labelled.
Lib Dem MP Jo Swinson said the proposals would challenge the "conformity of the perfect body image".
She said such images were "dishonest and harmful" and had contributed to the rise in eating disorders.
Lib Dem members in Bournemouth overwhelmingly backed plans to regulate digitally enhanced images and impose a ban on airbrushed pictures in titles aimed at the under-16s.
Photos in magazines and advertisements were being regularly manipulated, Ms Swinson said, to portray "perfect" images which were unattainable and damaging to most women.
These included doctored images of "whiter teeth, longer legs, flatter tummies and bigger breasts", she said.
"Advertising makes big money from images of flawless women," she said. "It is dishonest, harmful and it has got to change."
She admitted the proposal, which will now be adopted as party policy, would "ruffle" some feathers but argued the state had to take a lead rather than rely on the industry to change its practices.
She rejected suggestions the proposals would not work and that people would still be unable to tell whether models featured in pictures were genuine and had not had cosmetic surgery or been on a diet.
Legislation would not be required to force the change, she added, offering to work with the advertising and media industries as well as regulators to change existing codes of conduct.
Lib Dem party members said the move would force advertisers to be more honest and open.
One, Ettie Spencer, said "urgent" action was required as more and more young women were under "all-consuming" pressure to emulate celebrities and fashion models.