First, consider the possible reasons for using Google Search. You might be in correspondence with a potential new beau and he sends you a picture that looks like Clark Gable. You'd like to know if that is how he really looks. Or maybe you're checking for copyright violations of your image on your website, because you noticed someone is using the same image on Twitter in a defamatory way. Or you might be checking to see if a photo you see in the news is real or photoshopped. Or you might just be curious to see where it comes from and how the image is used. There are many more reasons to use Google Image Search. Now let's see how to use it.
The easiest way to work with Google Image Search is to download the image you want to search for. Once you've downloaded the image you need to find where the image is saved. For most Windows users that is in your Downloads folder by default. You can also right-click on the image and select "Save Image As..." and that will allow you to select the path. For images I have no intention of keeping, I save them to the /tmp folder on my Linux machine, that way they're deleted on the next reboot. Windows has a temp folder, too, but it doesn't get cleaned on reboot.
Once you have your image in place, open the folder where the image is and minimize or set it aside. Now open a browser and go to the Google home page. Notice in the upper right hand corner that there is an option for images.
Click on Images and watch the search box change.
Now bring the other folder on top like so...
Now click and drag the image of choice for your search and check the results. Here I just dropped in one of my screenshots for fun.
Google will search for anything that matches the image and if you're lucky, you find what you wanted. I hope you enjoyed this short tutorial.