In the original novelization, Padmé doesn't die in childbirth:
In the novelization of Return of the Jedi, written by James Kahn, Obi-Wan Kenobi tells Luke that Anakin didn't know his lover was pregnant when he became Darth Vader, and Obi-Wan hid her away to protect her. After she gave birth, Obi-Wan took Luke to Tatooine and she took Leia to Alderaan.
These events are completely retconed / contradicted in Revenge of the Sith.
In Children of the Jedi by Barbara Hambly, Leia mentions being raised by her aunts, suggesting that her adoptive mother died when she was young. However, Star Wars: The Annotated Screenplays states that George Lucas intended for Leia to remember her real mother, and Leia's Star Wars Databank entry states that her memories are of Padmé.
But as Mooz pointed out above, like her brother, she is force-sensitive even if she's never understood or trained her abilities.
This opens the door to all sorts of force-enabled flashbacks / images.