1. Media Gallery
I’ve check your site and i assume you’re referring on this page http://sindhuhadiprana.com/index.php/commercial-projects/. I notice ‘index.php’ on the page url and it might causing the problem. Please try to re-setup the permalink of your site. https://codex.wordpress.org/Settings_Permalinks_Screen
2. Social Media Button
Please check our documentation right here http://support.jegtheme.com/documentation/social-icon-favico/ about Social Icon. You just need leave blank all input fields.
3. Background Color
Please check our documentation right here http://support.jegtheme.com/documentation/website-background-setup/ about Website Background.