Kent,
-Once your spline is extruded, with your spline track highlited
-go to the textures tab. Click the checkbox next to “fr” for front
-change map method to clip; you’ll see in your timeline a front texture tack appear
-import in the still you want to use if you haven’t already
-drag and drop your still onto the front texture track.
-you may need to position and scale your image to fit it in
Hope this helps!
Tim