Place a shim.gif (transparent, 1pixel square dreamweaver gif) where you wish the image to show, and make sure it is the right size (same as the image).
Give it a name that you can remember in the properties inspector (image3 just doens't cut it)
Click on the item which will initiate the swap. Make sure that it has a link on it (put "javascript:void()" or "#" in as the link if you don't already have one). Open the behaviours inspector and click on the plus sign. Choose swap image. In the list of images on your page there will be your newly named image. CLick on that and set the image that you wish it to be. Leave the settings for "preload" and "restore on mouseout".
That should now work (fingers crossed)
The only thing you would want to change would be the initial image before the rollover. Derren
[Mediocre talent - spread really thin]