256色转灰度图 256色转成灰度 该功能用于将8位索引图转成灰度图。因有些绘图工具或处理功能必须在灰度状态下进行操作,所以我们要选择“256色转成灰度”功能将8位索引图转成灰度图-256 colors to 256 colors into grayscale grayscale of the function 8 is used to index into a grayscale map. Because of some drawing tools, or processing functio