Here's the basic process:
1: You shoot a photo.
2: It is buffered in camera RAM.
3: The RAM buffer is written to the card.
4: The images on the card are transferred through the wireless link.
5: When an image has been successfully transferred through the wireless link, it is removed from the card.
If the wireless link is interrupted, whether by going out of range, a problem on the receiving end, or whatever, images will build up on the memory card. Once the connection is restored, image transfer will resume and the card will be gradually cleared.