Also, when I add a graphic image (still picture) how do I tell DVDA to size the picture to its original size. I can determine the picture size manaally outside of DVDA, then enter the values in DVDA, but is there a way to tell DVDA to just size the picture to its original size?
This depends on the project you're working on. As an example, regular NTSC is 720x480 with an aspect ratio of ~0.9.
The easiest way to add a background image that will not be distorted is to create it as a 720x480 pixel image, bring it into DVDA and choose the "Stretch to fit" background option. Keep in mind though, that the content on the still image should be designed for an aspect ratio of ~0.9.