You can send messages and pictures that can be viewed for a specified amount of time. The item is hidden from the recipient in the chat until they touch and hold to reveal it. After the timer expires, the content can't be viewed.
Tap and select Timed Message.
Select how many seconds you want the other person to be able to view the item for.
Type a message or attach a picture.
Tap Send.
BBM is designed to alert you if the person takes a screen shot of the timed item. If you don't want to see the icon in chats, you can change your BBM settings.
and select Timed Message.