Hi
Create 2 pictures - 1 small 1 big
Create another picture - VERY small - set to transparent (you will need
photoshop or corel or something like this)
Add you small pictures to your page on layers - absolutley positioned
Add some more layers - each the right size to cover the small pictures
In each of these extra layer add a copy of the VERY small transparent
picture and then strech this to fit the layer
Add some more layers each with a large picture - set to visible = no
Possition these where you want - for you idea it would be best to possition
them over the corresponding small picture
Use a OnMouse Over (of the VERY small transparency) to swap the small
picture for the large picture
Hope that make sense
Here are a couple of examples using this method. (move your mouse around)
http://www.ukoutdoorpursuits.co.uk/
http://www.ukoutdoorpursuits.co.uk/page_photcredit.htm
There may be better methods of doing this but I am only a learner with
frontpage - so I just do what I can