I now have index.php in public_html with
include("/nfs/.../JohnDoe/contents/section1.html")
Then I have "section1.html" under /nfs/.../JohnDoe/contents/ and it has
<img src="/nfs/.../JohnDoe/contents/image.jpg">
and I put "image.jpg" under /nfs/.../JohnDoe/contents/. Then, the webpage does display "section1.html" but not "image.jpg."
Another thought might be that I can use
include("/nfs/.../JohnDoe/contents/image.jpg")
within section1.html. But then the question is "how can one set 'width' and 'height' of image.jpg this way?"