code: public static Sprite addBorder(Sprite original, int color, int size) {
  		int[] newPix = Arrays.copyOf(original.getPixels(), original.getPixels().length);
  		for (int x = 0; x < original.getWidth(); x++) {
  			for (int y = 0; y < original.getHeight(); y++) {
  				if (x < size || x >= original.getWidth() - size || y < size || y >= original.getHeight() - size) {
  					newPix[x + y * original.getWidth()] = color;
  				}
  			}
  		}
  		return new Sprite(original.getWidth(), original.getHeight(), newPix);
  	}
docs: Adds a border to a Sprite (the border is added inside, so part of the sprite will be covered)
  
  @param original The sprite to which the border will be added
  @param color    The color of the border (in ARGB format: 0xAARRGGBB)
  @param size     The sice of the border, in pixels
  @return The sprite with the border