Depending on the browser you use, there are plug-ins that will enable you to inspect the EXiF (camera settings) data on images. As an example, I use Firefox and a plug-in called FxIF. It allows me to right click and select properties on images. A dialog box comes up and I can see most of the camera settings if the photographer didn't strip the data. For instance, this shot of mine:
Camera Make: NIKON CORPORATION
Camera Model: NIKON D3
Image Date: 2009:04:14 19:18:12
Flash Used: No
Focal Length: 190.0mm (35mm equivalent: 190mm)
Exposure Time: 0.0063 s (1/160)
Aperture: f/7.1
ISO equiv: 200
White Balance: Manual
Metering Mode: Center Weight
Exposure: Manual
Exposure Mode: Manual
Give it a try!