This does indeed work
rule "Doorbell Pressed Closed"
when
Item GroundFloorHallwayDoorbell_DoorBellSensor changed from CLOSED to OPEN
or
Item GroundFloorHallwayDoorbell_DoorBellSensor changed from OPEN to CLOSED
then {
logInfo ("Door bell pressed closed", "doorbell pressed")
executeCommandLine("wget", "http://192.168.0.15/snapshot.jpg" , "-O" , "/home/openhabian/tmp/camfrontdoor.jpg");
Thread::sleep(3000) // 3 second wait
sendMail(getActions("mail","mail:smtp:guidhere"), "myemail@gmail.com", "the doorbell was pressed","mail body" , "file:///home/openhabian/tmp/camfrontdoor.jpg")
}
end