Some futher fixes

Update to make_master_im and image_chi function
-- can now choose the number of frames and step sizes more flexibly

Update to plot function
-- images are now dependent on a switch in the function definition being true or false

Other stuff
-- First attempt at fixing make_movie still plenty to do here
-- Error one line 79 when using [sample] --> TypeError: 'NoneType' object has no attribute '__getitem__'