The easiest way to save is number one were you just Copy the image from the website and then paste it directly into the document/presentation. Able to understand easily with out any further explanation. While number two the right-click and save the image in a folder on your computer is more time consuming and sometimes it is confusing, but number two is much more needed to learn if you just new in using computer. If I'm going to choose which one is much practical I will choose number one because it is more easy and practical .
There are two ways most people insert images into documents/presentations
1.) Copy the image from the website and then paste it directly into the document/presentation
2.) Right-click and save the image in a folder on your computer. The in the document/presentation click on the Insert table, select picture, and browse for your picture in the folder you previously saved it in.