Hover Zoom GOLD!
This Chrome extension will show an image if you hover over its thumbnail or a link. Also integrates with Reddit Gold to properly sync visited state for images (i.e. purple/blue links) across machines! If you don't care about the Reddit Gold integration, you should just use HoverZoom+ instead as it is more frequently updated. More details and all source code can be found on the github project page: https://github.com/superlime/HoverZoomGold