The bag containing the memory card was discovered it in a walkway alongside the River Wandle in the Haslemere Industrial Estate just before Christmas.
Detective Constable Riaz Karolia of Wimbledon Police said:
"So far we have had no success in locating the owner of this bag. I am hoping that by issuing these images, someone may recognise the people involved and we can start the process of reuniting the owner with their belongings.
"The memory card contains images of someone's special day - if you know who these people are, please get in touch."
Three nine-year-old boys who were injured when a tree fell at Spencer Cricket Club in Earlsfield, south west London, yesterday have been named by the club as Lewis Gaston, Aidan Oakley and George Roberts.
Aidan has been discharged from hospital while Lewis and George are remaining under close observation, the club said.
Three boys were in hospital, two with serious head injuries, after a tree fell on them.
The trio of nine-year-olds were waiting to use the practice nets at Spencer Cricket Club in Earlsfield, south west London, when the tree crashed down.
The boys, one of whom suffered leg injuries, were rushed to hospital and the club suspended all play. The incident happened yesterday after strong winds buffeted parts of south London.A statement from the club said the boys' conditions were being assessed.