Something that looks nice is fairly easy to do in vegas is to use the picture you are displaying as a background also, only blurred. To do this:
Create two video tracks.
Place the same picture on each track.
On the bottom picture, use track motion (the rectangular box on the right side of the video track identifyer). Make sure that your cursor is at the beginning of the event (picture) then stretch the picture so that it fills the entire preview window.
Once this is done, click on the gaussian blur FX and then drag the extreme blur into the bottom picture. You can slide the horizontal and vertical value bar further right to cause even more blur.
If you did everything correct, you should see the picture inside of a background that has the same colors as the picture.
Hopefully, this is clear and not too overwhelming since you are just starting out. But give it a try, you may like the results.