There is no built-in functionality for this in Publisher, but you can do
what you are asking. You might find it easier to use the Porta photo album
tool to produce both the thumbnail images and the larger pictures. You can
also use JAlbum and other tools that allow you to produce web formatted
photo albums. Porta and the others can create an html photo album that you
then upload to a subfolder on your website and then use iframe code to
import it to your Publisher page.
http://www.stegmann.dk/mikkel/porta/
Using the insert html code fragment tool, insert the following code snippet:
<IFRAME src="
http://www.yourdomain.com/album/index.html"
width="700" height="500" hspace="0" vspace="0"
frameborder="0" scrolling="auto"></IFRAME>
Obviously you change out your domain name, and what ever subfolder (album)
you create to contain your Porta html webpages. Make the code fragment box
large enough to accommodate whatever sized images you choose 700 X 500 seems
to work pretty well with 100 pixel width thumbnails and 480 pixel width
large images. Play with the width and height of the code fragment box and
within the code snippet until everything looks ok. If you upload the Porta
html files to your web host, then web page preview will allow you to test
your Publisher layout before you upload your revised Publisher html files.
You can also use an iframe to work out a solution if you want to control the
iframe from thumbnails inserted into your Pub web page, but I don't have any
ready made code for you. Just read up on using iframes and how to write the
code.
DavidF