This is an embedded background image? According to Access Junkie at
http://www.accessjunkie.com/Pages/faq2010_77.aspx the process is:
1. Take your form that has a background image or AutoFormat that you like
2. Right-click on the form in the Navigation Pane and select Export >> XML
3. On the first page of the wizard, select a destination to drop some files (Desktop is fine)
4. A small dialog will then appear with three check boxes
5. Select the first option (Data) and third option (Presentation) and then click OK
6. Click the Close button on the last page of the wizard after the export is complete
7. Navigate to where you dropped the files and, among other things, you'll find a new folder called Images
8. Open that folder to claim your prize