With FrontPage it is possible to change the currently applied theme, apply different theme to a site and create you own theme and apply it to a site. The downside is that only the site collection in which new themes or changed themes are created can use this theme.
When your theme has been applied and you would like to install it on the server so that everybody is able to use it, you are not able to export the theme. To solve this do the following:
- Open the site via FrontPage (File>Open Site)
- Browse to the folder _themes\<theme>
- In this folder you will find the currently applied theme with all the css files and images. Copy these files to your local machine and use them to create a server wide theme.