About a third of explicit images of children found online by an internet watchdog are selfies, new figures show.
Between January and November 2019, the Internet Watch Foundation (IWF) took action on 124,605 images of child abuse found online.
Of these, 30% were found to be self-generated - taken by the child in the image.
One victim, who wishes to be identified as 'Rhiannon', was sexually assaulted at the age of 13 in her own home.
The day before, she has been groomed online by a fake modelling scout.
Police contacted her months later after discovering images of the assault on her attacker’s computer.
Rhiannon said had the images been reported, she could have been safeguarded:
"In my situation, if the images that I’d sent to the perpetrator that evening had been reported and I was identified, I could have been safeguarded before the man came to my house, and that would have prevented me from being sexually assaulted.
"It’s easy to think that an image is something that has already happened, but you don’t know the circumstances.
"For some people it could be ongoing. A report could lead to them being taken out of that situation."
Under UK law, anyone can be prosecuted for taking, sharing or possessing explicit images of under-18s. The IWF, alongside a charity that supports survivors of abuse, is now calling on young men who find such images online to anonymously report it.
Chief Executive of the IWF, Susie Hargreaves, said the figures show the issue is "fast becoming a national crisis".
She said: "Today’s data demonstrates the alarming rate at which self-generated imagery is increasing, especially among young girls – often in domestic settings.
"These are images and videos where girls have been groomed, coerced and tricked into performing sexually over webcam".
The IWF works to get images of child abuse removed from the internet and is in contact with law enforcement agencies across the world.
Ms Hargreaves said it is important to make "efforts to halt the spread of" indecent images online.
"While we’re working to prevent images from being taken in the first place, efforts to halt the spread of the ones in circulation, by encouraging young men to anonymously report any they may unintentionally stumble upon, is an important and much-needed step to help tackle the issue.
She added young men can be "the heroes" that help "save many more victims of child sexual abuse".