This is kind of a complicated thing to do. I'd make the file cabinet objects first. Don't merge with the base image. Then manually slice it between the drawers, leaving space within each slice to the right for the open drawer mouseover state. Hit Ctrl+D to make a copy of the sliced page. Now you can edit the drawer objects to extend out to the right as if they were open. Save both images with File, Save for Web, As HTML.

There's two ways to create the rollovers. One is to open up your first page in your HTML editor and then do a rollover using the corresponding image from the drawer open image. For example, in Dreamweaver or FrontPage, it's easy to do a rollover this way. Both the closed and open drawer images are the same size because of the way you sliced it.

As far as doing this in PI8, it could be done, but it is complicated and probably would require a whole tutorial, instead of what I can do here. You'd save the second page with the open drawers as HTML. Then go back to the first image with the closed drawers and select a drawer cell with the slice tool's Pick tool. In the Slice Panel, create a rollover using the Script Effects, using the open drawer images you'd saved previously to a folder on your hard drive.

Stephanie's PhotoImpact Tutorials
PhotoImpact 8 and 7 Classes