Seems like you just need to insert background to your presentation. To do so,
click Format > Background. Click on the dropdown and select Fill Effects.
Select the Picture tab.
Click "Select Picture".
Look for the picture you want to insert.
Click Insert, then ok.
Click Apply to All so that the background is applied to all slides.
If you need to know more about creating templates, have a look at:
"Create or Customize Templates"
http://pptfaq.com/FAQ00313.htm
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Shawn Toh (tohlz)
Microsoft MVP PowerPoint
Site Updated: Sept 05, 2007
(Amazing PowerPoint animations, artworks, games here)
http://pptheaven.mvps.org
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