Very interesting piece of software, thanks for putting it out there. I've been playing around with hand painting normal maps for 2D skeletal animation, but doing it by hand takes time. This looks like it could be really helpful for generating a rough first pass, or for more static assets.
One problem I noticed was that the edges on some of the 32 bit PNG files I handed it are fading to white on the border between black and transparent. There is also a very hard inverse border on the normal map along that boundary unless I turn bump height all the way up to compensate. I'm not sure if this is caused by the program I used to create the PNG or something in Laigter.