Photo Gallery is not responsive "yet" Michelle...
I'd say that using Albums on S-Drive might be the best way to experience RWD before Photo Gallery gets an update, if at all. The fact that Apple & Adobe won't swap comics when it comes to Flash and the wonders therein means that the future is questionable for Flash apps.
There is no special code for responsive design. It's really just a case of taking responsive display options into consideration with your layout design (buttons, images, menu's etc.) and then using CSS to configure the site differently for different visiting resolutions.
The secret is in the media queries aspects of CSS. You can easily make most sites responsive once you obey some basic guidelines.
Dave