Google Chrome: Lightbox is a widely adopted image-preview script — if you've ever clicked on an image and had it enlarge within the browser you've experienced Lightbox. Image Preview is a Chrome extension that brings Lightbox-style previews to all sites.
Even if you're on a site that doesn't have Lightbox, you can still enjoy that in-tab enlarging of images by downloading Image Preview. Once Image Preview is installed all images you click on will enlarge within the current tab and provide an in-tab view of the larger image instead of opening the image by itself.
Just like with Lightbox, clicking anywhere on the screen — including the enlarged image — will remove the dimming mask and the image and return you to the normal page. Image Preview is a free extension and works wherever Google Chrome does. Have a favourite extension? Let's hear about it in the comments.