public static Sprite getSprite(String filename)
	{
		// Try to load the sprite from the cache
		Sprite rval = (Sprite) resourceByString.get(filename);
		
		// If it's not in the cache, try to load it from disk
		if(rval == null)
		{
			try {
				rval = new Sprite(filename);
				resourceByString.put(filename, rval);
			} catch (IOException e) {
				// File not there/wrong format, return null
				return null;
			}
		}
		
		return rval;
	}