A phone safety expert says society will have to learn to deal with the growing problem of porn on mobiles.
As a man was jailed for sending thousands of porn images, many of them to children, John Carr of children's charity NCH predicted software would filter unwanted calls in the future.
In the meantime he said phone users could programme their handsets to avoid calls from unknown numbers.
But the genie could not be put back in the bottle, with mobiles here to stay.
His comments came as Royce Roberts, 42, of Caernarfon, Gwynedd, was imprisoned for four years and three months for the random sending of what could be tens of thousands of porn images.
"Sending inappropriate material by mobile phone is very widespread," said Mr Carr, who wrote a report for NCH (formerly the National Children's Homes) on the dangers of the new breed of mobile phones.
"Happy slapping incidents are entirely the product of the opportunity to send inappropriate material.
"People have always had cameras but they did not carry them around all the time, they were only taken on holidays or bought out on special occasions", he said.
"Now people have a camera on their phone which has massively increased the number of images they can take," he added.
While networks are expected to develop software to filter out certain images, Mr Carr said there was action that could be taken now by many phone owners, such as programming handsets to accept only recognised numbers.
"If anyone is worried because they are receiving unwanted text or pictures they should report the mater to the police and the mobile phone company, and if possible put a bar on the number where the messages are originating," he said.
However, he said it was "too late to put the genie back in the bottle" in the era of the mobile phone.
"There's no point in throwing the baby out with the bathwater - we have to learn how to deal with inappropriate calls," he added.