When I say that I can't generate textures on the fly, that's not entirely accurate. It's possible, but it would mean changing built-in code is the Display class, which would not make this plug-in a separate, single object, which could be imported no matter what you've already changed with the built-in code. A suggestion to BlueMonk: Add a TextureRef subclass that can generate textures directly from bitmaps instead of from names of built-in images.
It's certainly possible to get snowflakes in a graphic sheet and just choose from those. Mostly, the reason I implemented the snow at all in the first place was to show off how cool things can get when you really get into it, generating content from the internet on the fly. Which reminds me that I still have the project to get new content (i.e. maps) from the internet somewhere around here.