Is it possible to use the width of the paper as a variable in order to set the width of an imported graphics? For instance when I want the picture size to be the width of the paper, minus 3 centimeters, or half of the paper's width etc.
The answer is simply to use
you could use
Refer to http://en.wikibooks.org/wiki/LaTeX/Page_Layout#Page_dimensions for useful page dimensions commands.