ImageReady creating extra images

What I have is a basic navbar, sliced up with basic rollover states. The problem is that when ImageReady exports the images, it creates copies of the rollover states. I haven't defined any secondary rollovers or anything like that so I'm really confused as to why this is happening.

I have set my files up to save as slice name_rollover state and the new files are saved as slice name_rollover state_trigger name (which is the default setting - don't know if that's a coincidence or not)

Anyone know of any possible reason for this? I might have inadvertantely done something to cause it but I don't know what that could be.