It's back to school time in the northern hemisphere, a time of year when social media feeds are filled with photographs of grinning children wearing spotless uniforms on the first day of the new school year.
This week, over half — 53 percent — of UK parents will plan to share snaps of their youngsters on the doorsteps of their homes as they set off to school, attracting comments like: "Aw, so cute" and "How time flies".
Yet when four-year-old Lucy Lewis starts Reception this week, her mother Nicola won't be posting any pictures of this milestone moment.
When Lucy was just two years old, she was stalked by a stranger who collected all the happy family snapshots Nicola had posted online — and re-posted them on more than ten fake social media accounts, interspersed with shots of a pornographic model of the same name.
Mum of one Nicola, 33, from Bromley, Kent, says: "I used to post sweet snaps of Lucy in a new dress or playing with her toys on my Twitter feed, which only had about 200 followers, including lots of friends and family.
"Then one day I got a notification that a complete stranger was re-tweeting my photos. When I looked, this person's feed was full of them. I couldn't tell who it was as the profile picture was a cartoon character, the location was given as Canada, and they used weird, made-up names.
"When I sent a message asking why this person was using my child's image in such a disturbing way, they never replied."
Panicked, Nicola, who works as an artist, blocked the account only to find more kept popping up over the next month, on both Twitter and Facebook, with some using her child as the header picture — until eventually she had to call in the police.
Nicola says: "You think: 'There are billions of pictures of kids out there, why would anyone take an unhealthy interest in mine?' But then it happens to you. It was terrifying. I felt like I was being watched constantly."
Yet despite risks that include attracting the interest of paedophiles (horribly, it's often photos of children in school uniform that hold most interest for them), fraudsters and even burglars, this week UK parents will add millions more pictures to the 1.3 billion they post on social media every year.
A third of them, often revealing the schools children attend (through badges and logos) and even clues to addresses, such as door numbers, will be shared on accounts which are not private, according to new research released by cyber security firm McAfee.
And this week, it became all too clear just how many cruise the web with dark intentions. In a speech to technology giants, UK Home Secretary Sajid Javid revealed there are at least 80,000 paedophiles active in the UK on social media. A crop of fresh new photos flagged with hashtags such as #firstdayofschool2018 (which on Instagram alone brings up 2.5 million images) gives paedophiles a vast new library of images to comb through.
According to security expert Will Geddes, the author of "Parent Alert! How To Keep Your Kids Safe Online", many parents have no idea how their perfectly innocent picture of precious family memories can be used in disturbing ways.
One way photos can be abused is "deep faking" — in which normal childhood pictures are manipulated so that the head of a child is superimposed onto another's naked body or adult pornographic images. They are then uploaded and shared via paedophile sites.
Millions more gleaned from parents' social media accounts are not tampered with at all. Yet the lurid comments from users make it clear their interest is unhealthy.
Mum-of-two Gemma Hawkins, from the South-East, was shocked to discover how her eight-year-old son's pictures were being used without her knowledge. As a result of her experience, the only people Gemma, 31, will be sharing start-of-term pictures of Teddy and his sister Lilly, six, with are her parents.
Gemma says: "I always thought I was careful. I posted pictures on Instagram, but I kept my settings private. But then in January, I got a friend request from a modelling promotion page and I accepted. Now I feel I was naive, but at the time I thought it was harmless.
"Not once did I send them any pictures of my son or give them permission to use his pictures.
"But within a few days, I started getting over 100 friend requests a day from men I didn't know. When I clicked on the profile pictures, there were no faces, but images of child pornography.
"Then I saw pictures of my son on the modelling promotion account. From my feed, and without my permission, they'd taken a picture of him playing on a rope swing and also messing about with some paint, so he'd had to take his shirt off.
"There were comments like 'handsome lad' and 'good looking boy'. I felt sick.
"I messaged the account to ask them to take the pictures down and they ignored me.
"I reported them to Instagram and they didn't do anything, so I closed my account. I felt terrible. I'd failed Teddy because it's my job as a mother to protect him.
"It really opened my eyes to how easily photos of children can be stolen and misused."
Yet it's often photos of children in school uniform that most interest paedophiles, a taste fostered by easy access to the huge number of openly available pornographic sites with titles such as School Uniform Porn, featuring young adults dressed up as pupils, the Daily Mail reports.
A quick look through recent court reports of paedophile cases illustrates how many ask victims to send pictures of themselves in their school uniforms while they are grooming them.
Will Geddes says parents must also bear in mind how easily school badges on blazers, sweatshirts and rucksacks can lead predators to your child's exact location.
"It opens up to an undesirable person the opportunity to think: 'Oh, that's where that child goes to school.' While they are more likely to just circulate pictures, I don't think you can discount the risk that they develop an unhealthy interest in the child or the school."
In the vast majority of cases, parents will never have the slightest inkling of how their child's pictures are used for the sexual gratification of predators, says Will.
Police have to prioritise investigating images that show children being actively abused and don't have time to trace parents when pictures of children in uniform are found.
Alexandra Neil, 32, from South-West London, is another mother-of-two who was shocked to discover more than 30 photos of her children stolen from her Instagram account.
"Two weeks ago, I had a private message from one of my followers saying she'd seen some pictures of my children posted on another page, under another woman's name, pretending they were hers."
While they had used the children's real names, the captions were different and the woman was saying how she looked forward to seeing them.
Alexandra said: "The page had been set up a few weeks earlier and already had nearly 400 followers.
"It was extremely scary, especially as the profile was fake. There was no evidence this woman existed in real life. I told them to stop, but I never heard back and eventually Instagram took the account down last week. It made me stop wanting to put my life and family out there."
While Alexandra was never able to find out why the page was set up, another possible reason for the theft of children's photos is the disturbing rise of what are known as "baby role play" pages on the internet, in which Instagram users create bizarre fictional lives using pictures of other people's children.
But beyond sexual or fantasy uses of such snaps, experts also point out that "first-day-of-school" pictures open up your family to crimes such as burglary.
Consumer security expert Pete Turner, of cybersecurity firm Avast, says: 'Firstly, they give away the school a child attends.
"Secondly, posting that photo online is likely to disclose the family's home address. Today's smartphones include location trackers, which applications like Instagram and Facebook use to determine someone's location.
"More often than not, people grant these applications permission to track them when they sign up for the service, often without realising. So, in a couple of clicks, the two locations where a child spends most of their time could be exposed. To a lesser extent, it could also help a burglar to approximate the times of morning or evening routines, such as school runs."
Doorstep pictures could even put your child at risk of fraud in the future, according to research by Barclays Bank, because they provide valuable insights that fraudsters can exploit.
The bank warns that an innocent first-day-of-term snap could be used to circumnavigate a security question such as the name of someone's first school, which is the kind of security question someone might use to access bank accounts when they come of age. Information like this can also be pieced together to fraudulently take out a credit card or a bank loan in the child's name.
Indeed, Barclays experts predict that, by 2030, the trend for "sharenting" will be the reason for two-thirds of online identity fraud against young people. Will Geddes believes that even though the National Crime Agency and other bodies are doing all they can, parents must be on the front line.
"Ask yourself, would you feel comfortable leaving the photo on a table in a public coffee shop?" he says. "Are you happy there's nothing that a stranger could benefit from seeing?"
For Nicola, the stalking of her daughter ended after two months when the person behind it contacted her via the call app FaceTime on Christmas Day, after finding her mobile number on the website she uses to sell her art.
It turned out to be a mentally disturbed teenager in Canada who had created a fantasy in her head that she was friends with her daughter. Nicola said: "I answered the call from a Canadian number I didn't know and there was this young girl. I hung up immediately and blocked the number."
However, the call meant she could persuade the Canadian police to trace the number and visit the girl's family. "The girl lived with her grandparents, who had no idea what she was up to on her iPad in the bedroom. I don't know how she found Lucy or why she focused on her.
"But it showed me there are people out there who will fixate on young children and I am not prepared to give them any bait."
Some names have been changed.
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