Childline is stepping up a campaign to educate teenagers and their parents about the dangers of sexting after a rise in the number of calls about the issue.
The charity said sexting was the most-viewed topic on its website last year while counsellors dealt with 2,634 calls on the issue.
The Zipit app, designed to help teenagers refuse requests for sexual images of themselves, has been updated to give young people a gallery of images and animated GIFs they can send to deflect requests with humour.
Childline and the NSPCC are also looking to educate adults about sexting after a survey last year showed almost half of parents in Scotland are unaware it is illegal for a child to take nude selfies.
The 2016 survey also confirmed that while more than a third of parents fear their children will be involved in sexting, only 33% spoke to them about the risks.
Matt Forde, head of NSPCC Scotland, said: "Many young people tell Childline that they feel pressured into sending sexual images of themselves and don't always have the confidence to say no.
"Once a teenager sends an image of themselves they have no control over where it is shared or who sees it, and sometimes images can end up online.
"This can leave a child feeling humiliated and even lead to them being bullied or blackmailed.
"By using humour, Zipit helps young people take control of online chatting that becomes awkward or pressurised, and support them if something goes wrong."
First launched in 2013, Zipit also includes advice on safe online chatting and what young people should do if they feel threatened or if an image becomes public.
Childline founder and president Dame Esther Rantzen said: "The online world is full of opportunities for young people but also presents dangers like sexting which they need help to withstand.
"Senior police tell me that sexting has become normalised for far too many young people, so many teenagers feel pressurised into sending explicit pictures of themselves.
"There is a real danger that they feel desperately humiliated and it can sometimes result in them being abused or bullied into handing over money to prevent these images being shown to school friends or family members.
"Zipit gives them the weapon of humour so that they can resist this pressure in a way that feels appropriate and cool.
"Many parents have told me they feel helpless when they try to protect their children against these dangerous pressures, so I'd encourage families and professionals to take a look at Zipit and share it with the teenagers they know."