How to create a frame for still photos

I'm using Sony Vegas Movie Studio Platinum.

I'm trying to create a video that comprises of a series of still photographs that fade in one after the other. The photographs come in all different size aspect ratios. They are already cropped to contain only the important elements of the photo.

The end result is that I get a black background on two sides of the still because obviously the screen depth to width ratio is always different to the photo ratio.

Is there someway for me to create textured colour to replace the standard black.

Or better still....is there someway for me to place each still photo in a full colour frame.

In PowerPoint it is easy to place still photos into frames...but I can't seem to work out how to do it in Vegas.

If some-one could tell me how this is done I would be VERY grateful.

Cheers Bob Barrow