Yes, my widths are a power of 24 =).
I have another problem: it seems Keen:Vorticons (atleast) can't handle differently sized sprites for different animation frames. Is this an issue with ModKeen or is it inherent to Keen itself?
More sprite width issues...
Well, sometimes you can creatively use the pink-on-grey hitbox thing. In Lego Keen, when I brought in the sprite animation that replaces the Vorticon's death animation, I realized I calculated wrong, and that I'd need a width of 49 for it to animate correctly (instead of 48). Fortunately, though, I had an extra couple of pixels on one side, and so I moved the hitbox over by one pixel, and everything aligned perfectly.
A better way to describe this would be if you had a sprite that waved around a large hammer. In frame 1, his arm is holding his hammer behind his head, but in frame 2, his arm is holding his hammer in front of his head. If the pictures are, say, 24 pixels wide, you would probably have to have an area 32 pixels wide for the picture to be in for it to line up properly, but if you just move the hitbox to a new position, it will line up, and you won't have to waste pixels on the left or right side of your frame.
I don't think any of that made sense... a picture would definitely be worth a thousand words here... oh well.
A better way to describe this would be if you had a sprite that waved around a large hammer. In frame 1, his arm is holding his hammer behind his head, but in frame 2, his arm is holding his hammer in front of his head. If the pictures are, say, 24 pixels wide, you would probably have to have an area 32 pixels wide for the picture to be in for it to line up properly, but if you just move the hitbox to a new position, it will line up, and you won't have to waste pixels on the left or right side of your frame.
I don't think any of that made sense... a picture would definitely be worth a thousand words here... oh well.