I can see that you can make particles use an image, but it doesn't seem like you can make them rotate the same way you can make them move around. it would be nice to have various features, like having particles rotate in the direction they're moving, or spin them, and other things. Another seemingly useful addition would be to use any number of random images for a single particle generator instead of using just one or none at all.
Another thing I'd like to point out and ask about is the picture editor. It seems really badly put together, with most buttons lacking descriptions (especially ones that do need them), scroll bars not actually staying in the window (they're half under the rest of the window!) and the "style" list for the shapes seems cut off, with only 4 selectable styles and what looks like a small piece of a 5th fill style. The rectangle that should be surrounding the style list is cut off like that as well.