Clearing Gallery - Using the Featured Image Option
The Clearing Gallery stack is a great stack to use to make awesome looking galleries. There is a great option to this stack that allows you to show only one image, a Featured Image of the gallery set, then the rest of the images will show up in the lightbox.
After you have added the Clearing Gallery stack and the Clearing Image stacks, choose the image you want to make your featured image. Once you have done that, click on it and look at the Clearing Image stack and you will see the settings below.
You will want to check the box by Featured Image?
Then you will want to click on the Clearing Gallery stack. Look at the stack settings, and you will see a check mark on a box called Block Grid Layout
You will want to uncheck that box. When you do, the stack settings will change, and you will see this:
Now you will want to check the box marked Featured Image Support? Once you do that, the image you choose as a featured image will be the only image on the screen until it is clicked.
Now go forth and make your websites great!