I think it would be pretty useful if the picture editor not only showed how many pixels down and right your cursor is, but how many up and left it is too.
This would make aligning the bottom of the image with the bottom of the hitbox easier, when using images of varying heights.
-The Player hitbox is 80px tall,
-Frame 1 of an attack animation is 80px tall,
-Frame 2 of the same animation is 75px tall,
If I were to use the same X,Y coordinates for both images the hitbox would be 5 pixels out in frame 2.
It's certainly a very minor thing, but it's just something to make things a little easier.