Spencer Ackerman and James Ball:

Rather than collecting webcam chats in their entirety, the program saved one image every five minutes from the users’ feeds, partly to comply with human rights legislation, and also to avoid overloading GCHQ’s servers. The documents describe these users as “unselected” – intelligence agency parlance for bulk rather than targeted collection.
One document even likened the program’s “bulk access to Yahoo webcam images/events” to a massive digital police mugbook of previously arrested individuals.

In other words: I think it is safe to assume that if you ever “showed” yourself on a webcam, there is a high likely hood that an image of you may be saved on a government server somewhere.