Render of Background image is distorted

I've been trying  a number of things to get my render to match what I see in the design window with little success.  My background image gets stretched, usually horizontally, with the addition of a grey border (see attached screenshots. My specific goal is to add some 3D text with a glass material to a high resolution image. 

I've tried using the match image feature, setting the output resolution of the camera output to match the original resolution of the image, turning on and off the override camera size in the render settings and using different background images.

One screen shot is of the design mode and the other is the output of that screen after rendering.

I'm guessing this is easy to do but I just can't seem to get it.  Thanks for any help.  George