Your messages are secured during their entire life span. They can only be read by you and your recipients on authorized devices.
Wickr then deletes all metadata from its communications and our Secure File Shredder cleans the RAM after each message or picture is deleted.
We unfortunately can't prevent someone from using a camera to take a picture of a message on a screen, so we always recommend that you only send information to someone you trust.
If you'd like to know more about the technical details of how we keep your messages private, please feel free to read about it here: Wickr's Core Crypto Goes Public, or for a more concise version, here: How Wickr's Security Works.