Here is how to apply rounded corners:

Step 1: Login to your EXAI account and open the website in widget mode 
Step 3: Click the style tab (A). 
Step 4: Click corners icon (B).
Step 5: Choose the corners (C) and type in the length (D)or use the slider.
Note: You can also adjust the corners from widget mode under the style tab.

Note: You can make an image circular by adjusting the corners under style. To make the corners rounded set the length to 180px.

You can make the corners of any layer or element rounded so that they can give a more attractive look. You can do this very easily and give a radius to the corners up to 50%. You can also make selected corners rounded and apply the corner property to those only.