Note: This step will vary depending on where the image is located. This particular image, "Hawksbill Sea Turtle Carey de Concha", was taken from Wikimedia Commons.
When you view the image at its original site you can see if there are any licensing requirements, get a correct URL, and find out much more information. The image above is from Wikimedia Commons. By looking at the image on Wikimedia Commons you can easily download a variety of sizes of the image, view any licenses associated with the image, and even find the correct way to attribute the image.

Clicking on the "Download all sizes" button brings up this screen. As you can see it shows you the correct URL, gives you a variety of file sizes, and even shows you the best way to attribute the image.

If you scroll down the page you will also find a summary of the image and an explanation of any licenses that are associated with it.
