The photo was discovered by police officers after they arrested the drug dealer's client and went through his phone, reports the BBC. The photo showed the man holding up a bag of ecstasy tablets in his palm.
It was sent to South Wales Police's scientific support unit, who uploaded the image to their images database. But since only parts of two fingers were visible in the photo, police officers could not find a match with other fingerprint records in the national databases.
Using other bits of evidence, the police officers managed to link the photograph to a suspect they had in mind. Once they arrested the drug dealer, they were able to match the fragments of the fingerprints in the photo to the full fingerprint of the suspect.
"While the scale and quality of the photograph proved a challenge, the small bits were enough to prove he was the dealer," Dave Thomas from South Wales Police's scientific support unit told BBC. He added that the case has now led to many other police officers trying to crack their cases in a similar manner. "It has now opened the floodgates and when there is part of a hand on a photograph, officers are sending them in."
"Fit for a detective story! How blown up fingerprints in WhatsApp images are used to arrest a convict, you can't estimate the power of social media," warned one person.
"Bloody! The potential of this is quite scary even as it has such a useful application," tweeted another.
"Pro-tip: don't take high-res pictures of your fingers (and fingerprints) holding illegal drugs and then share them with your family and friends. The cops will be very happy to use those against you," wrote a third person on Twitter. Click for more trending news