This shows how the mouse hover html widget can be used for smaller pictures.  I've set the style options for the container in the head portion of the html code to 360 pxl wide and 240 pxl hght.  As long as the picture is a gif, with some transparent background, a smaller picture can be used as above.  If a jpg is used, we don't have the transparent background.  The gif doesn't have to be 360 x 240 as long as it has the right aspect ratio.

This is the  widget code:

<a class="nowandthen alt"><img src="http://s424384483.initial-website.com/s/cc_images/cache_44353004.jpg?t=1342789453" id="image_44353004" alt="" width="300" height="200" name="image_44353004" />
<img src="http://s424384483.initial-website.com/s/cc_images/cache_44353904.jpg?t=1342789476" id="image_44353904" alt="" width="300" height="200" name="image_44353904" /></a>