Canadian teenagers are increasingly finding themselves in trouble after images of themselves get posted on the internet, says a group that reports cases of child sexual exploitation.

"We're seeing an alarming number of examples where adolescents are taking compromising or nude photos of themselves, sharing them with friends, and then that information is getting disseminated," said Signy Arnason, director of cybertip.ca, a child exploitation tip line started in 2002.

The tip line launched a campaign for teens Tuesday as part of Safer Internet Day in an effort to make them aware of what can happen to their photos and to ask them to pause and think a moment before posting.

The tip line is run by the Canadian Centre for Child Protection, a non-profit group that raises awareness about child safety.

In more than six years, five per cent of 30,000 tips have been received from teenagers, Arnason said.

Many of those cases involved a young person who has either posted a picture of himself or herself on the internet or forwarded a nude photo to a boyfriend and then regretted that after the photo has been shared with others, she added.

"It's something you can't change," Arnason said. "Once you've done it, you're not going to be able to correct it."

She suggested that many teens don't think ahead or beyond the small group of friends they want to share the photo with. But there's no guarantee everyone in that group will protect their privacy.

The group's "Respect Yourself" campaign sends that message to teens through a website and a booklet that will be distributed to 300,000 Grade 7 students across Canada.

Besides warning teens about photos of themselves, it asks them to be respectful of others and to get their friends' permission before posting photos of them.

And it notes that even non-compromising photos can include personal information that lets people identify the people in the photos or clues such as team jerseys that could be used to track a child down.

The group also suggests that parents set a good example by not putting their own photos and personal information online.

Feds renew national strategy

Public Safety Minister Peter Van Loan also recognized Safer Internet Day on Tuesday, announcing that the federal government is renewing Canada's national strategy to keep children safe from online predators.

The program had been set to expire this year under sunset provisions, but Van Loan said its renewal allows police the tools to combat child victimization and increase public awareness of the dangers facing children on the internet.

RCMP Supt. John Bilinski, head of the National Child Exploitation Co-ordination Centre, said the renewal also allows more officers to get specialized training and technology needed to successfully investigate child abuse cases.

Safer Internet Day was also celebrated by other jurisdictions around the world. The European Commission used the occasion to launch a campaign against cyber-bullying and the Council of Europe posted online the third edition of its Handbook on Internet Literacy.