I have only Photoshop CS3 on my imac. I don't want to add an entire creative suite. I'd like to find out what I need to add video and to paint on video, rotoscope, using pictures from Photoshop. Can anyone help?
If you have Photoshop CS3 Extended, there is the ability to open video files in Photoshop and use the retouching tools on a frame by frame basis. It's not what I'd call true 'Rotoscoping' nor does it provide roto-masking.
The following help topic should get you up-to-speed: