The ImageGallery extension supports the template technology, allowing you to completely customize an extension's appearance and layout.
The look of the ImageGallery extension's default elements can be modified by creating a specific template, which defines how an element will be rendered by a client browser. The ImageGallery extension allows you to create templates for the following elements: fullscreen viewer item text, fullscreen viewer text, and item text. You can apply templates for all identical elements within the extension (using extension level templates) or for a particular element (using item level templates).
In this demo, the SetItemTextTemplateContent property is used to display information (name and email address) about items. The SetFullscreenViewerItemTextTemplateContent property is used to display information about items (name, email address and phone number) in the full screen viewer.