When parents post pictures of their children on social media they invariably either look cute or beatific. Not the ones posted by Dubliner Stephen Crowley of his now almost two-year-old daughter, Hannah.

We see lovely young Hannah perched precariously at the top of a staircase, brandishing a dangerously sharp looking kitchen knife, standing much too close to the edge of seaside pier and climbing up a narrow ladder into an attic.

Stephen Crowley and his daughter in the kitchen. Stephen Photoshops the perilous scenarios to raise awareness of the Bone Marrow Registry

The pictures shock on first view. How can any father do that to his young child? The early judgments online were condemnatory. Crowley “should be a shot” and is “the worst parent in the world”.

The pictures, though, are not what they seem. They’re not real, they are all Photoshopped, and Hannah is never in danger. And there’s a very good reason for Crowley to try to grab people’s attention through a shock tactic.

Stephen Crowley’s photo of his daughter Hannah on an attic ladder

Hannah learns to drive. Stephen has a coffee

When Hannah was four months old, she was diagnosed with a rare immune disorder called Hemophagocytic Lymphohistiocytosis. She spent the next four months of her life in hospital receiving chemotherapy. She needed a bone marrow transplant to survive but because not enough people put their names on to the bone marrow registry, it was difficult to find a match.

“Because Hannah was in isolation for so many months and missed out on so much early on, as an inside joke, and using my Photoshop skills, I sent photos of her in precarious situations to family and friends” says Crowley.

“At the time we were looking at a situation where, of the 27 million people globally on the bone marrow register, only three were a match and two of them weren’t ideal. We did get a match with a German woman and that worked. So that one person in 27 million saved us.”

“Because of the way the register works, the donor must remain anonymous although we were able to send her (through the German blood service) a letter and a hand-print of Hannah’s”.

Hannah balances. Photograph: Stephen Crowley

Hannah climbing. Photograph: Stephen Crowley

Crowley decided to upload the “Hannah in precarious situations” photos to his public Instagram account (@steecrowley) to raise awareness of bone marrow donation.

As a product designer for a software company in Dublin, Crowley has been working with Photoshop most of his career so the photographs have an ultra-real feel about them.

“There are tricks you can use to make them look real: lighting is a big factor” he says. “It’s something I’m not going to keep doing, as I don’t want Hannah to be recognised when she’s older. My main motivation for making them public is to draw people’s attention to the existence of the bone marrow registry.

“Also, it’s important for people to understand that giving a bone marrow transplant is a relatively straightforward procedure these days. People have horrific images of providing bone marrow but that just isn’t the case”.

The whole experience has been a bit of a learning curve for Crowley about people’s online behaviour. “I would get people saying things like “you should put your daughter in a really dangerous situation like throwing her out of an airplane” which is totally missing the point of the photos. They have to be believable in order to get a reaction from people”.

Oddly, when Crowley posted a normal photo of Hannah on his Instagram feed (Hannah getting christened) he lost 500 Instagram followers. “I’m thinking now of what would be the most normal and safe photo of Hannah to post, just to see how many followers I lose,” he says.

Happily, Hannah is looking to start creche next year and then go on to a local primary school. Because of the success of the Hannah Instagram feed, thousands more people both in Ireland and beyond, know about the bone marrow registry and how it saves lives.

Woopsadaisy! Photograph: Stephen Crowley

“For us as parents, the pictures are also something to show Hannah when she is old enough to understand them, along with a the reason I took them,” he says.

You will find the link to the Irish Bone Marrow Registry at giveblood.ie. See more images of “Hannah in precarious situations” at instagram.com/steecrowley