There's nothing new about fake news, or indeed political disinformation in the mainstream media.
Leaving aside that nowadays the boys on the right would be just as likely to be beaten up for being "posh" (not to mention English and white) as the boys on the left would have been back then, the photograph is hopelessly posed and the title itself is both misleading and probably no older than 2004.
In fact the boys on the right are not "toughs" but pupils at a local Church of England school. They'd taken the day off school for a trip to the dentist and then decided to earn some easy money by helping out at the Eton-Harrow cricket match that was taking place at Lord's that afternoon. Sime has clearly, er, solicited their aid for his photograph (presumably for a small fee). And given that nice young Anglican boys would generally have been discouraged from walking around with their hands in their pockets, he's presumably also instructed them to adopt the poses their holding - apparently to make them look as if they're quietly masturbating. The two Harrovian boys though just happened to be standing at the gate at the time waiting to be collected by one of their parents, and by all accounts they were persuaded to pose for the camera with neither their parents' consent nor any financial emolument.
The picture is of course well known in England, and a good example of indigenous English leftist propaganda - that is to say the lies we like to tell ourselves. It was first published in the 10th July 1937 edition of the News Chronicle, a leftist newspaper that later merged with The Daily Mail (which of course by modern standards isn't even considered leftist). The screechy agitprop caption read 'Every picture tells a story'.
The real "story" of the photograph - of the tragic fates of the two "toff" boys and of the long, happy, normal lives of the "toughs" - is now freely available on line thanks to dear old Wikipedia.