How to enlarge the view of an image on a webpage?

How do you zoom/enlarge an image on a webpage? In this case, the image is a sample page of a book and without enlargement, you can't read the text.

I do know how to increase the size of text on a webpage, but my question is about images.

I couldn't find any postings covering this, but I am a new MacBook owner, so the answer may be obvious, but I can't find out how using the Safari Help.

Thanks