Custom tags are a great way to apply static information. For example, if you have numerous templates and want to apply a logo across all templates, you can create a custom tab as a placeholder that references a logo. Now all you need to do is enter that placeholder into the template and the logo will be displayed.
On the eBay Settings select Custom Tags. Now enter a name for the tag, and create the logo in the html editor. When entering the tag into the template, remember to place the placeholder symbols before and after the text of the tag.