In Pages, you can add a shadow to an image. This is what the it looks like:
If you have ever designed a colour document on your computer and then printed it out on your inkjet or laser printer you may have noticed that the colours come out slightly different. This is partly to do with the fact that printing with ink on a piece of paper is a different process to creating colour on a computer monitor, but it is possible to calibrate your monitor so that the colours match up as closely as they can. This article gives you some tips on basic monitor colour calibration.