This video tutorial explains how to create an animated photo mask effect in Adobe Flash. The mask effect uses a motion tween to reveal the colour image on a black and white image. It looks like this:
To achieve this effect you will need two copies of the same image (one in black and white and the other in colour) and both images should be exactly the same size. You will need to use three layers – one for the black and white image, one for the colour image, and the other for the motion tween and mask. You need to make sure both images are in the same position on each layer.
Watch the video below (or on YouTube) to see how to apply this effect.