Chroma Key on Multiple Images. does anyone know how?

I'am working with short animated clip, in FCE 4 actually, and i need to make animated character to move in real footage. I have finished ~ 700 pictures of that character, so what i don't understand is, how to delete white background out of so many pictures... Any suggestions? (p.s. I can create independent movie clip out of these images and then delete white background, but in this case i will lose quality, so it is my plan b)

What program was the characters created in? Or is this footage of real people shot in front of a white background?

Stephen Smith
Utah Video Productions

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it was closed circles character (in fact, character was just a animated talking lips on real footage woman's breasts). i used photoshop for rotoscoping, but my mistake was to save all these frames in jpg. i should have save it in png, so FCE could read it without background layer, which in my case, was white.