Hmm... it might work that way, but I haven't seen anything like that. Say each sprite was a square that was 50*50 pixels each.
To get the first image you'd use something like
NPC Code:
showimg 101,bogo_dog0.gif,x,y;
changeimgpart 101,0,0,50,50;
changeimgvis 101,3;
That would show the first sprite, the still dog from behind. Now, say you wanted the image of the dog sitting down while facing toward the player. You'd just do something like:
NPC Code:
if(dir=2&&stuff){
changeimgpart 101,100,250,50,50;
}
That would take the image and edit the part that's showing, giving you the dog sitting down. The actual dimensions are a little different that a 200*300 pixel image, but that's the general idea. Hope that helped.