Ideas:

+Make png2art palettize images if not all ready. This will require loading a palette.
+Also, make sure palettized images corrispond with palette.
	+ If not palettized correctly, convert image to proper palette so true-color PNGs could be used with warnings.
+Make art2png/png2art have a single-file mode, like art2tga/tga2art only had. This is for people who want to work on one file at a time.
+Comment code better