In this case, the sum of the 9 numbers -1,0,1,-2,0,2,-1,0,1 is 0. We can not devide the number of red, blue and green by 0! So i put if statement in the code.By using the if statement, we erase the brightness because we can not put minus number in the code and any number bigger than 255. And we get the edge of the picture, which is the combination of red, blue and green.
The second one is also focusing on the edge of the picture while change the color into blue Again, the third one changes the color into red. Mine new one is try to change the background and show the deep color of the original picture.