You can place images of any size or proportions in galleries. They can open in FancyBox if you wish or link anywhere.
You can use from 1 to 20 columns layout, but I think the example layouts below look best:

Example galleries:

You can also have a scroller-type gallery:

With grayscale effect, as well:

Galleries can be used as standalone pages or as a part of bigger content.
Of course open or boxed layout may be used for any gallery page.