There was one Ning help tutorial related to your question. It was posted a few years ago. You can try searching this on the discussion archives. I'll see if I can find and pull it out for you--
Here it is:
By Kyle of Ning!
Hope this helps
Ron - THANK YOU THANK YOU THANK YOU! It worked and looks great. I really appreciate your help. - Christine
I have recently changed my site from a two column to three column layout. This change has affected by slider. I have been able to figure out how to change the width of the slider but I can't figure out how to adjust the length. I want it to be 500pixels wide and only 300 pixels Do you know how I can adjust it. Our community is at http://myhealthshare.org.
I think you can click on the html code for the slider and play with the dimensions.
Where do I access this code? In the CCS code or, the analytic area or the text box itself?
I'm sorry. I wish I could help you but I'm not an expert on this at all. I think you should start a new discussion within this community and the experts will definitely help you.
You can access it via the text box itself. As for the CSS and styling, you need to place it on the Appearance Editor or Design Studio.
You can also try Eric's updated slider tutorial here:
Hope this helps.