NextGen Slideshow

I’ve reached out to NextGen with questions about their slideshow with no response. So i turn to you fine folks.

1. How do you add captions to the slideshow?
I tried in the description field under the alt text, but it didn’t appear.
See this link for a screen grab of what I tried.
http://yousend.it/JZv1su

2.The horizontal photos look great, but the vertical pics are aligning left. Is there a way to get them to center?

This link has a picture of what’s happening
http://yousend.it/I2lVRs

3. Is there a way to change the speed of the transition between photos during the slideshow? I’d like it to go faster.