Imagus is a Hover Zoom Replacement to Enlarge Images on Mouseover
Chrome/Firefox/Opera/Safari/Maxthon: Hover Zoom, the tool that previews full-size images when you hover your mouse on a thumbnail, has recently been embroiled in controversy with issues of malware and privacy. It's best to play it safe in such aspects and Imagus is a worthy replacement for the same functionality. Plus, it works on several browsers and across most popular websites.
Zoomable objects are marked with a customizable outline. Every aspect of how the zoomed image will look can be tweaked to your liking. And most importantly, when you don't want it, you can disable the function for a single image or the whole session with customizable hotkeys.
Imagus also includes a lot of other customizations for images in your browser. It replaces the default image viewer and you can set the size that an image will be displayed (such as fit to width), zoom with the mouse wheel, change the page background colors, and more. Play around with the Settings menu and you'll discover that almost every aspect of Imagus can be customized to your liking.