I guess that you could pick a site that you like and download its HTML and CSS to learn from, although make sure that you don't go ahead and use the whole thing, obviously - it's someone else's IP after all.
However - I'm a bit concerned about what method you might be using to develop your site and the fact that you're almost certainly not yet familiar with any HTML/CSS. I don't want to push you too far out of your comfort zone, although you'll find that you need to come at least a little way out.
There is such a thing as a plugin photo gallery that you can drop into a site, but I can't speak for how easy or effective they might be, or where you might find one.
Content management systems like Joomla/Drupal/ModX are good for building galleries and don't take much skill to set up and use. The ease of use is the whole point of them, really. They need a server with support for a database though.