See alternative text of images. Displays alt texts as tooltips. Configurable.
Some browsers show alternative text of images (the content of "alt" attributes of "image" tags) as tooltips (popups). Such behavior was formerly very popular, and lots of old and new web sites still rely on it. Almost all modern browsers, including Chrome, show alternative text of images when you turn off the image loading only, and the tooltips show the "titles" of images if they are set.
This extension lets you see alt texts of images in tooltips. The extension is configurable, so you can choose how alts and titles are displayed and combined. If you want to differentiate alts from titles you'll be able to enter the prefix to be shown before alt texts in tooltips.
Known limitation: You will probably not see alt texts of those rare images which are dynamically added by scripts.
*** Another useful extension will let you see what you are clicking by adding a visible focus box around the links you click: