Unable to return to her adventures as Batgirl following her crippling at the hands of the Joker, Barbara Gordon keeps various items of nostalgic value on her computer desks that remind her of who she once was while working as Oracle.
One of these items is a framed black and white picture of herself as Batgirl; possibly taken from a newspaper.
Initially keeping it on her desk in the Clock Tower, she gave it to Cassandra in repayment for saving Barbara's father, James Gordon, from Cassandra's father, David Cain.
In spite of Cassandra now possessing it, the picture stayed on Barbara's desk while Cassandra lived in the Clock Tower. It is unknown wether Cassandra kept the picture when she was relocated to her own Batcave.