Hi Ambersandwich and thanks for your answer
I tried, but couldn't get it to work. Like I said I'm a newbie :/
So what I did was that I replaced my values of my outermost div, which I guess is the div around my picture in the index page (only did testing with my main page). I didn't really know what that width is that you pointed, guess it was the div's width? Still, only get my picture where I didn't want it: right side of the page, not center. I don't feel so smart right now
I'm goint to start a webpage making course, but it's almost a year of waiting