I'm not sure what you were trying to accomplish, sallyanne, but what you got was really a messed up animation.
I played with your image to make it smoother. These are the results.

Get the Animation Settings and Combine background/Overlay background scripts by saulgoode. They are practically essential for making animations. Settings sets the timing and replace/combine modes, the Combine background one does just that. Create a background for your animation and it puts it on each image.
They are listed under Animations on this website:
http://chiselapp.com/user/saulgoode/rep ... pt-fu/home