Even better, figure out the scale difference between the old images and the new images, then choose "other file actions/Save as Resized project (and images)" from Spriter's menu and choose the new scale, and folder location for your rescaled clone of the entire project. Finally, once its done creating your clone of the entire Spriter project, (folders with resized images and all) then replace the auto-rescaled images with your new, hand redone images.
cheers.