I don't have another means of creating a 16-bit .png myself, or I might be using that method instead of Paint. But, one of the things I was trying to do with it was use the image to create a terrain map for a 3-D program. This one requires 16-bit grayscale .pngs. Attached is one of the default images included in the program.
Thanks for the plug-in. I'm sorry to say that it's not working for me though. When I go to file properties, it says that the 16 bit (65000 color) .png files are 32 bit depth files, which won't work for my purposes. The .bmp are actually saving as 16 bit images though.