This problem is optional. Solve it only if you can!

You can apply with the previous 3 tasks.

In a programming language of your choice, implement the following function/method:

convertToGreyscale(imgPath)

Given the path of a color image (.jpg, .png, .bmp) create a greyscale version of it and save it.

original

greyscale

WARNING! You are not allowed to use any libraries, you have to write your own algorithm!