I believe that two very simple user controls would do.
The second control would be just a place-holder, to simply arrange the images. You could use even a table here, or generate it dynamically based on the number of images placed inside.
For the site as a whole - yes, I would use a template and a theme, then just plug in different content in every page.
If you have any more questions, please feel free to ask.
the Telerik team