The Gallery plug-in generates a thumbnail grid from the images in a
library. Clicking on a thumbnail pops up the full-sized image.
To add a Gallery to a page, simply insert the Gallery plug-in, and select the library to display from the list provided.
Image captions will also be shown in the thumbnail grid. This
works best if the captions are brief, otherwise they will dominate the
layout.
The Gallery works best if you have thumbnailed all of your images
first. Square thumbnails give the tidiest layout, but if you
retain the original image shape you can still get fairly neat layouts
by applying some CSS to make the grid cells a fixed size and giving
them a background shading, which helps to make the grid appear more
uniform.