Dumming down the image gradient formula

Hello

I was wondering if anyone could dumb down what is happening in the formula that discribes how an image is gradiented. I can't understand what the formula is doing. The link to the formula is here: Image gradient - Wikipedia, the free encyclopedia

Any help would be greatly appreciated.

Thank you

Re: Dumming down the image gradient formula

Well, how "dumb" does it have to be? Have you ever taken a Calculus course? What, if anything, do you know about partial derivatives and the "gradient" of a function of two variables?