C＃对象空引用异常 - 不确定如何设置数组值

I guess I'm not setting the array correctly or something, but this throws a "nullreferenceexception" when it gets to the line where it actually sets the new array value to the color_table array (should be the 7th and 12th lines of what you see below). How should I write this so that it works?I guess I'm not setting the array correctly or