When you open an image in Photoshop CS that doesn't match the current working space, you are given a choice to:

1) Keep the embedded ICC profile (this is most usually a different Photoshop working space, but may be a scanner profile or camera profile). Keeping a profile, overrides the selected Working Space, and it will be used to preview the image as opposed to viewing through the selected Working Space.

2) Convert the image from the embedded ICC profile to the current Working Space in Color Settings. Converting an image file changes the data. We think that this should be used only when you have clear reasons for converting from one color space into another. For example, you may have older images which have been worked with while under the default sRGB space of Photoshop 5. If you are previewing in the AdobeRGB 1998 Working Spaces - you would want to convert your older images so that they previewed in the new Working Space as they did in the previous.

3) To discard the ICC profile and not color manage. This means that the image comes in without an embedded profile. But it does take on whatever the currently selected Working Space is. So "no color manage" might be better worded as color manage manually. In this case, the sRGB image from 2) would not be converted and would therefore preview differently from its last session.

Our recommendation is to Convert once you have decided on a Working Space. Our recommended Working Spaces for printing images are AdobeRGB for desktop printers. You can at any time assign another Working Space profile or even convert from one Working Space to another with Image/Mode/Assign Profile or Image/Mode/Convert to Profile.

Photoshop CS has a live Preview which is modified by both the RGB working space and the Proof Set up (this is where you load one of our ColorSupport ICC profiles). Go to 3 - Proof Setup.