I have followed the instructions in the following post to set a custom style for a popup window used for a link in an image map:
viewtopic.php?f=12&t=5518&p=29471&hilit=style+class+image+maps#p29471
To summarize:
I created the html.popup_autosize style class.
I set the Box Width and Height properties to Auto for this style class.
I created topics that contain the image I want to link to (These topics contain only an image - no other content)
I set the style class for these topics to popup_autosize.
I opened the image map and linked to these topics, setting the target to Popup Window.
When I compile the size of the popup is the same as it was before I created the style class. That is, it is much larger than the image..
I am posting in the hope that someone sees the error of my ways!
Thanks for your help.