Here are the top 10 free image viewing libraries in JavaScript:
PhotoSwipe: A touch-friendly image viewer for mobile and desktop.
Lightbox: A simple, unobtrusive script used to overlay images on the current page.
Magnific Popup: A responsive lightbox & dialog script with focus on performance and providing best experience for user with any device.
Swipebox: A responsive lightbox plugin for jQuery.
FancyBox: A tool that offers a nice and elegant way to add zooming functionality for images, html content and multi-media on your webpages.
simpleLightbox: A lightweight and easy-to-use lightbox plugin.
A simple lightbox: A lightweight image lightbox plugin.
FooBox: A responsive image lightbox plugin for WordPress.
Colorbox: A light-weight customizable lightbox plugin for jQuery.
baguetteBox.js: A simple and easy to use lightbox script written in pure JavaScript.
These libraries allow you to display images in a user-friendly manner, with options for zooming, panning, and other interactive features. They are highly customizable and can be easily integrated into your web projects.