You got farther than me. My entire browser window was filled with a headline and a background image, so I just moved on.
In this case the background image adds absolutely nothing to the user experience or conveys what the content is about, if anything its quite an example of bad design and interferes with the user for no good reason! The "web developer" has added it just because he could not because there is any good and thought out reason to use this "image page monstrocity"
This is my personal website. I also use it to showcase my photographs. I agree that they don't add anything to the content.
Its just funny seeing same mistakes being repeated and various "trends" employed by web developers for no good reason other than "because we can, and it looks cool", but thats ok for personal projects since you are exploring what can be done.