what are you trying to do with it?
ImageReady is really for slicing up an image created in Photoshop to save out as a HTML page [with the images saved as .gif or .jpg] with all the rollovers, rather than coding the whole thing.
I don't have the software on this pc, so i can't double check on these instructions
From Photoshop, theirs a button on the bottom of the toolbar that will send the image to ImageReady.
From their, use the slice tool to divide the image up into smaller images. Their should be a window somehere on the screen that displays all the current slices for the image.
From this window [right-click i think or theirs a menu] where you can select add rollover state. Click on the rollover part for this slice, and click the visiblity on/off button on the layers window.
Eventually... goto
file->save optimised as
and save the html file, the images are saved in a directory [generally called \images] in the same location. open the HTML file in IE [or any other browser] and it should have a working webpage interface...
hope that makes some sense...