I know this is really a noob question, but it has always confused me. If something says "Images must be 210 px high and up to 375 px wide." how do I do that? I assume one uses a program to do it, but which program? Or maybe just cropping?
I know this is similiar to this question
but I am not a programmer. The difference between that question and mine in that I need the answer in not-a-programmer language.