Prior to today, the image our system would select to show in the category pages was chosen at random. Since this isn't always ideal, we've added a feature so you can choose which image is used in situations where IB randomly selects an image to represent your article.
The home page features will still be manually chosen, so this won't represent what shows up if you are home page featured.
To select which image gets featured, go inside the IB editor and scroll down until you see the elements/image tabs on the right hand side.
Beside the element tab is the image tab. Inside the image tab you will see a button called feature. Click that and you will select that image to be featured.