From pprid...@gmail.com on December 31, 2011 22:39:50

What do you need to do? It'd be cool to be able to edit an animation directly in a sprite sheet, so that no extra import/export steps would be required... just load/edit/save the sheet without multiple frame files. How would you like to do it? Just specify the size used for each frame in the sheet, and then edit as a normal image or animation... either editing the sheet directly, or one frame at a time using the same view as the current animation editor.

Original issue: http://code.google.com/p/aseprite/issues/detail?id=64