do I have to learn digital signal processing(dsp) to take on image processing?

I 'm not aiming to become computer scientist but rather I notice there's a algorithm called fourier and after some research ,I found out it's under a dsp.I took a peek on some of the dsp books and pretty intimidated by how thick it is.

Actually not the thickness of the book that bothers me but rather the inside of the book,those cryptic enigma codes inside.I always flunk my maths exam.But alas,going to programming world...I'm glad that I have to see all those terrible math equation.OH how wrong am I,I realize that favourite area of mine in C++,graphics require solid foundation in mathematics.But enough of me and my phobia of mathematics...

So my question is actually, what area of mathematics do I have to understand to create program like photoshop???