One last note. In
its present state, i.e. using the main timeline of the movie, the movie will
loop endlessly and it is of course the endless looping that changes the image
through the text every two frames. There may be a time where you want to place this effect in a movie
instance where, unless otherwise instructed, it will not repeat. In the “Writing Mask” layer, place a
keyframe above the last used frame of the “Image” Layer. Click with the right mouse on that frame and
choose “Actions.” From the list of
Basic Actions choose “Go to” and change the information accordingly if you need
to.