First you create a TimerListener class by extending the TimerListener interface. Implement a method called timedOut() as the interface requires. Everytime the timer clicks, this method will be called, so I assume you want to update your LCD image here.
Then make a timer object that uses your timerListener - specify the delay and your TimerListener:
Timer(int theDelay, TimerListener el)
The rest is pretty self explanatory from the API docs for Timer.