Select the Insert menu and then select More Gadgets.
Open up the Insert menu in the Google Sites Editor You will be able to see a list of gadgets you can add to your site, like Links, Tables, and Images. Click on the More Gadgets option. This allows you to install customizable tools such as the POWr Media Gallery to your site.
Copy and Paste URL
You will see the Gadget manager. Select Add Gadget by URL. Then paste this URL into the field. Click on Add to finish.
After you add your new Media Gallery Widget to your page, you're probably going to want to adjust the shape and size of your Widget. Use the different options in the window to select the height and width of your plugin. If you'd like, you can add a border, title or scrollbar to your Media Gallery Widget, but we don't advise it. You will have more editing options through the plugin.
Set up POWr Media Gallery
Visit your live Google Sites website and select the settings gear in the upper right corner of the Media Gallery Widget.
In the POWr Editor, click Import Existing Media Gallery, find Media Gallery- and click Copy.