You can help your site visitors get a better look at an image by clicking on it and expanding to a full size version in a lightbox. To launch an image in a lightbox follow these steps.
Step 1: From the WebStarts editor upload your image and place it on the page.
Step 2: Click to select the image and then click the attached cog icon.
Step 3: From the panel scroll down and be sure to check the box labeled Lightbox.
Save your changes and they’ll be published to your live site. View your site and click on the image to see the effect.