When viewing a camera you can save a current snapshot to your photo album by clicking on the snapshot button. Any menus or graphics will be ignored and you will get just the camera picture without overlays.
If you have toggled the menus off and are viewing full-screen video, simply press the device's HOME and SLEEP buttons at the same time to perform a snapshot. Since this is a firmware induced full-screen capture it will not remove overlays (like PTZ controls or menus).