ScreenToss can be toggled on and off. Screen shots taken by the system when ScreenToss is disabled will not be uploaded.

Option-click the ScreenToss menu icon, or Select Disable ScreenToss from the ScreenToss menu to temporarily turn ScreenToss off. The ScreenToss icon will become gray.

Option-click the icon again, or Select Enable ScreenToss to resume uploading behavior. The ScreenToss icon will return to normal.

You can also enable, disable, and check ScreenToss’s status from the Preferences window.