This demo site has code that automatically builds a gallery from images placed in the html websites thumbnail and images folders to save you having to add code separately for every image.

Pure Css and Javascript gallery with thumbnail-list, detail/info view and fullscreen image viewer

Responsive JavaScript (jQuery) image gallery and lightbox with swipe gestures.

A handy study in the construction of a JavaScript Gallery, which features a primary picture (with a copy in previews), and 2 other images that can be clicked to reveal the larger image.