chapter "Image Processing" needs to be update

[edap]

http://openframeworks.cc/ofBook/chapters/image_processing_computer_vision.html

see thread in the forum:
https://forum.openframeworks.cc/t/debugging-error-appears-in-the-instance-of-ofimage-function/27669/2

it is not the first time that this question arises.

Feel free to assign this issue to me, maybe @golanlevin or @brannondorsey (as author and editor) can have a look later?