If you are pressing the camera button on the Zviewer app and it is not saving an image to your camera roll on your iPhone, then please follow these steps to enable this feature.
1. Go to the Settings menu in your iPhone.
2. Select Privacy.
3. Select Photos.
4. Then make sure the Zviewer applicatoin is set to ON.
5. You should now be able to press the camera capture button on the lower right, and it will save a screen shot for the image of the window that is selected with the red outline.