The Dink Network

It can affect hit boxes because they are measured from the edges of the whole image, so if it's an animated sequence it is easier for the image to be the same size for each frame (even though the sprite will change size) so the hitbox won't change shape.

The only other difference it would make that I can think of is that if you have lots of white space then cutting it off would make the file size smaller.

Edit: Whoops, hit boxes are measured from the depth dot, not the image itself. Thanks Cypry