I am back-end Web developer trying to learn front-end best practices and skills. I was wondering what is the best practices to layout on HTML/CSS when a designer sends an .psd/jpg splash of 1650x2500px.
Making some measures it looks that the content ( main info) is inside a 960px width but some images are big as the 100% width of the page (1600px). To me, the header and footer visual elements looks bigger that normal.

What I need to do? just slice from visual elements(logos,buttons,info-graphics) exactly as the size of original .psd?

Have you some tips or opinions?

Thanks so much!