Well what a coincidence, I have a sony cybershot and a Mac as well. A year ago the first time I ever tried stop motion I did the same exact thing. I never tried stop motion again untill a few months ago. Sadly, the Cybershots cord is on the bottom (at least the version I have) so that means you can't have it on a tripod (which is an absolute must). If you are willing to buy a new camera, many people use webcams I am sure you could find one on ebay for cheap, and if your not willing to buy anything you are going to have to press the shutter release button (This se would be your very last option!) and if you do choose to use that technique make sure you come in from the side and press the button and not from the top. Edit: I am now using a Canon Powershot with RemoteCapture DC for capturing the frames.
iMovie is good for editing your animated scene but not for animation, I would highly recommend iStopmotion for animation. Another (and the only other) option is framebyframe it is very slow and at first complicated. If you have any other questions just ask. 


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Lego Batman Joker Returns