When putting down a "Guided Image" object, I choose not to display the object at startup. I would like this object to be displayed when i hover or click my mouse over that part of the picture. However when I click or hover my mouse, the "Guided Image" object is displayed, but without the included image file. Only the text is displayed. But when I set the same "guided image" to display at startup, the included image file is displayed.

Stephen I don't have a clue what you mean by a 'guided image', anyway what you need to do is.....
Add the object you want to be displayed on a roll over. Add a Notifier object to the page, this should be the same size as the object you want to show.
Now at the page level add an display action on-display, set this to hide the oject.
Now add an on-mouseover display action to unhide the image AND another display on-mouseout to hide it again.
Simple :)