Rollover image and Tracing image

[soul999]

Hey i'm just wondering what is the difference between a rollover image and tracing image?

[blueprint]

I use tracing images as an overlay when using dreamweaver. You can set them up to display various screen resolutions to see what the site will look like on various monitors and where the 'fold' points will be etc.

Rollover images are just 2 (or 3) images that swap when rolled over or clicked on