image differences on different monitors/computers

[skimmilk68]

I just checked out a couple of my pictures from the Apple store on their latest computer with the wide monitor and my pictures appeared much brighter with more noise.

Was it just the monitor or does the computer actually effect the true quality of the picture?

[Jesper]

No two monitors and computers have exactly the same contrast and brightness. Even if you have two monitors of the same brand and you set the settings the same on both, there might be a difference in brigtness, contrast and colour.

To make sure that images look reasonably the same on different monitors and printers, people are using colour management systems and they're calibrating their equipment.

Here is an introduction that tells you what colour management is all about, what colour spaces and ICC profiles are, and how monitor calibration is done: http://www.drycreekphoto.com/Learn/color_management.htm