Thanks Greg! I was wondering what is the normal computational time for warping --- I cropped out two small stacks of image to test the warping tool,  each stack is ~ 28 MB (500* 500*50 pixels). This does not seem a very intensive job, but it took over 7 hours on my laptop to finish a warping job with grid size. The affine registration took only ~ 3 minutes though. Did I do anything wrong?

P.S. my imaging samples are larval zebrafish brains with GCaMP6s expressed in neuronal nuclei.

Best,
Dan