A pioneering fingerprint technique used to convict a drugs gang from a WhatsApp message "is the future" of how police approach evidence to catch criminals.
An image of a man holding ecstasy tablets in his palm was found on the mobile of someone arrested in Bridgend.
It was sent to South Wales Police's scientific support unit and helped to secure 11 convictions.
These are believed to be the first convictions in Wales from fingerprints taken from a photograph.
The unit's Dave Thomas described its use as "groundbreaking" and said officers are now looking more closely at photographs on phones seized for potential evidence.
He said: "It is an old-fashioned technique [fingerprinting], not new.
"Ultimately, beyond everything else, we took a phone and looked at everything on it - we knew it had a hand with drugs on it.
"These guys [the dealers] are using the technology not to get caught and we need to keep up with advancements."
The photograph came to light after a tip-off drugs were being sold from a house in the Kenfig Hill area of Bridgend.
It was raided and large quantities of Gorilla Glue - a type of cannabis - was recovered.
Mr Thomas praised the officer that spotted a photograph among a stream of WhatsApp messages going back months as potentially carrying significant evidence.
"It had a number of texts such as 'what do you want to buy?' on it," he said.
"There was then the photograph of the hand holding pills that seemed like it was sent to potential customers saying 'these are my wares, I'm selling these'.
"But he was not thinking it showed part of his hand and there was potentially a fingerprint."
The scientific support unit - a joint venture between the Gwent and south Wales forces, based in Bridgend - was able to scan the image into its system.
However, there were just parts of the middle and bottom of a finger visible - records only keep the top part.
This meant the image did not find a match on national databases.