So long as you make an image with a 3/4 ratio, it'll work. So an actor image consists of a single 32 X 32 box, laid out 3 times for the width and stacked 4 layers for the length. If you take a 96 X 128 sprite sheet, you can see it maintains this ratio 96 / 3 = 32 : 128 \ 4 = 32.
For a single pictured object, the sheet will be Width/3 and length/4.
