code: public void setTileSetImage(Image image) {
  		tiles = new SpriteSheet(image, tileWidth, tileHeight, tileSpacing,
  				tileMargin);
  		tilesAcross = tiles.getHorizontalCount();
  		tilesDown = tiles.getVerticalCount();
  
  		if (tilesAcross <= 0) {
  			tilesAcross = 1;
  		}
  		if (tilesDown <= 0) {
  			tilesDown = 1;
  		}
  
  		lastGID = (tilesAcross * tilesDown) + firstGID - 1;
  	}
docs: Set the image to use for this sprite sheet image to use for this tileset
  
  @param image
  The image to use for this tileset