Let’s say you wanted to capture a few images for a fade effect, which means you need a sequence of rapid screenshots. Here’s a script I’ve been using:
i=0 ; while [ 1 ] ; do i=
expr $i + 1; screencapture -C $i.png ; sleep 0.1; done
Hit ctrl-c to kill it, then view the sequence with gqview or something. Then use the very cool Flysketch to grab the same position each time. Caveat: The 0.1 millisecond interval is optimistic, the powerbook seems to handle only about 3 pics per second.
The camera sound effect helps a lot as you know precisely which instant got taken and also creates the requisite fashion shoot ambience.
The alternative would be to record it as a screencast and pick out the frames. I was using Wink under Linux, but haven’t looked into OSX tools, any suggestions?