Firefox add-on FxIF allows you to view the hidden EXIF data for any photo through the right-click menu.
EXIF data is a set of hidden fields within a digital photo that contain information about the picture. EXIF data includes camera data such as exposure settings, camera make & model, and the date the picture was taken. EXIF data may also include the photographer’s name, keywords that describe the photo, and copyright information. For a complete description of EXIF data, check out “EXIF: The Hidden Data Inside Your Digital Photos“.
FxIF makes it extremely easy to view the EXIF data for any photo displayed in the browser window. Install the plug-in, restart Firefox, and then right-click on any photo (CMD+click for Mac users with a one-button mouse). When the context menu appears, click on “Properties”. The properties window will display the EXIF data among other image details.
Link via photo.net Digital Darkroom forum.