X-Cart 5 uses responsive design out of the box. For the most part all images added to cart are responsive and adjust accordingly based on screen size.

If you are planning to add images as part of the second category description these images may not adjust if screen size changes. To make then responsive you can do one of the following to things:

1. When adding images assign "img-responsive" css class to them:

OR

2. Add new css rule in the X-Cart 5 custom css - under Look & Feel menu item:

.category-description-2 img {display: block;max-width: 100%;height: auto;}

Either one of these will make images added to second category description responsive.