Looks great, hope you get your code clean and soon can send patches. Why the buttons on the right top of the open-dialog are empty?
Answer: Hack n' slash. I have no reproduction of the mechanism for checking which images *should* be alpha blended, and which should not - the code assumes all icons should, and so in the case of 16-bit icons the alpha channel is fixed at constant 0, and so will these icons are drawn with 0% opacity!
This is one of many things that need to be finished in my work, but the proof-of-concept is there.
Joel