If you use Google Image Search to download the full sized version of images from the results page, you must have noticed that Google makes it a two-click process. The first click take you to the original web page from where the image comes. Only on the second click you get to download the full sized image as it appears on the page.
This is not necessarily a bad thing. For one, it allows you to actually visit the page and hence learn the context of the image. Another reason is the protect the copyright of the image, if any, by making the user aware.
If you need a quicker way to get the full image fast, you can install a Firefox extension called Google Image Help.
After you have installed the addon, just right-click on any thumbnail on Google Image Search results page and choose Open full size Google image to open the image in a new tab.
That’s not all. If you click on the addon’s icon in the status bar you can grab the original version of all the images currently displayed in the results page all at one go.
Greasemonkey users can use the Google Image Help userscript that does the same thing. This works on Opera too.