Zoom.js is jQuery plugin for image zoom. It's the best way to zoom an image. It transition/zooms in really cleanly..
bigpicture.js is a library that allows infinite panning and infinite zooming in HTML pages.
jQuery.imageView is a jQuery plugin that can help you to make image viewing with zoom.
Zoomerang.js is a drop-in library that allows your users to zoom in on (almost) any element on your existing page. It works even if you resize or scroll your page.
Smoothproducts is a simple, lightweight and responsive product image viewer using jQuery.
EasyZoom is an elegant, highly optimised jQuery image zoom and panning plugin supports touch-enabled devices and is easily customisable with CSS.
Ion.Zoom is an easy image lightbox jQuery plugin for small galleries. Allow to zoom images at place. Also supprort keyboard controls with ESC, LEFT and RIGHT button. Supports multiple independently operating galleries in one page. Works on touch screen devices (iPhone, iPad, etc.).
SergeLand Image Zoomer is free jQuery image zoom plugin the magnifying glass effect.
Snipe is a jQuery plugin to add a sniper-lens-style zoom on images. Snipe makes zoom effect over images that follows the mouse.
Panzoom is a progressive plugin to create panning and zooming functionality for an element.
Rather than setting width and height on an image tag, Panzoom uses CSS transforms and matrix functions to take advantage of hardware/GPU acceleration in the browser, which means the element can beanything: an image, a video, an iframe, a canvas, text, whatever.
Nivo Zoom is a lightweight and simple image zooming jQuery plugin. This plugin support for 5 different zoom types and allow us to add HTML caption.
elevateZoom is a free Image zoom plugin with options for window zoom, inner zoom, lens zoom. Tinting and easing can be enables. It is distributed under GPL and MIT license.
Hover-Zoom jQuery plugin