If Lightbox is enabled, an image will be expanded to full-screen when clicked on. You can set a color for the lightbox background and adjust its transparency. If you enable ‘Add to gallery’, visitors will be able to switch between the images on your page directly in the Lightbox mode.
You can enable Lightbox for multiple widgets simultaneously: to do so, select these widgets (Shift+click) and turn on Lightbox. The 'Add to Gallery' button can be also activated for several widgets at once.