And another question: is it possible to mix states in an object, i.e have the mouse away state be an image, and have the mouse over state be text?
No, images and text states cannot be mixed. But you can easily turn multiple objects on and off, so you could have a text and image item sitting on top of each other and change which one is visible.
You can create an image containing just the text on a transparent background, and use that for the mouse over state. It would give you the appearance of mixing both image and text states. But the image would need to be the same size as the mouse away state.
These tutorials are great, keep em coming!