You mean in the third section of the sprite bitmap? Currently the clipping section of the bitmaps doesn't work. At least AFAIK. You must edit the coordinates in the text file.
I've made a
program that I threw together. IMO it makes it much easier to edit the clipping and origin--via a dragable clipping region overlaying the sprite. It also has a few other handy features (importing at the click of a button, etc.)
As to the origin coordinates Andrew Durdin had this to say:
The origin of the sprite is the point of reference used for it in the
game. Essentially, it marks where the "position" of the sprite is
relative to its picture. This is particularly useful with animations.
Consider the yellow "hand" creature from Keen 5: the sprite images used
when it's rotating can all be sized to avoid wasted space (for example,
when it's vertical, it is a tall thin picture; when horizontal it's a
wide, short picture), and for each image the origin can be set to the
point about which it rotates. In this way, although the images are all
different sizes, and the point of rotation is drawn in a different
location in each image, they will all appear in the right place when
animating.
Or consider the wormmouth: the point of origin can remain the bottom of
the sprite: so with the "attacking" images, when it suddenly becomes
much taller, the sprite position remains the same, although the
y-coordinate of the image on the screen is lower. If the origin of each
sprite was fixed (as in Keen 1, 2, 3) to the top-left corner of the
sprite image, then you'd need to have larger bitmaps for each different
picture, with wasted space in most of them.
Another example: If you set the originY of the "Demo" sprite (4SPR0005.bmp) to 60, it'll show up near the center of the screen :)