Themes in the Portal Catalog 
Themes are stored in the folder in the Portal Catalog. Here you find:
The themes delivered by SAP
Your own themes
Caution
Make sure that you keep all your themes in the Themes folder (or a subfolder) and do not distribute themes to other locations in the Portal Catalog using Copy/Paste, as you can do with all other Portal Catalog objects. Themes should remain in their dedicated folder and not be moved to other locations.
When you save new themes in the Theme Editor, you can specify to save them in the Themes folder or in subordinate folders. For details, see Changing Style Parameters and Saving New Themes.
If you want to distribute theme administration across multiple administrators, you can create additional folders below the folder, store your themes there, and assign user permissions for these folders. In this way administrators can access different themes. See also Themes and Permissions.