Well, first of all it will be entirely geared towards handling PNGs at 48x48 resolution, so the editor will be straightforward to use for other game projects.
If people like it, I'm also wiling to enable a 24x24 export, although I'm sure people know where to find the resize tool (it's extra easy because Shiny Sword Sprites are 50x100 with a 2 pixel width padding

).
So far it has all the relevant features from the tile editor, it can import png's and it can save sprites to png. Also, I just got an 'additive load' working.
The additive load will allow you to load a sprite, and then "add" its contents to the existing sprite in the editor. This is particularly helpful for humanoid sprites, because you can make 'head' sprites, 'armor' sprites, 'clothing' sprites and trivially reuse those in different contexts.
Later on, I'm also considering to put in a widen/narrow button, so that you can change the width of your sprite in an approximate manner with the click of a button (in the case of widen you will need to adjust the central row of pixels manually afterwards to reflect something sensible).