There are a few things wrong with your code.
(1) You will need to load the 'juicebox.js' file into your web page for your gallery to appear (like in the sample embedding code in the Embedding Guide).
Change:
<script src="/People_gallery"></script>
... to:
<script src="/People_gallery/jbcore/juicebox.js"></script>
(2) There should not be a Doctype Declaration within your gallery's embedding code.
Remove:
... and ensure that the embedding code is within the <body> tags in your page.
(3) You have closed off the new juicebox({ section too early.
Remove:
... just below the baseUrl entry.
(4) The baseUrl should point towards a gallery folder (not a file inside the folder).
(5) You need a comma after the baseUrl to separate it from the configuration options which follow.
Change:
baseUrl : '/People_gallery/index.html'
... to:
baseUrl : '/People_gallery/',
(5) The code you posted has a stray </div> tag at the end of the code. This can be removed (unless it refers to an opening <div> tag that you did not include in your post).
You should now have embedding code which looks like this:
<!--START JUICEBOX EMBED-->
<script src="/People_gallery/jbcore/juicebox.js"></script>
<script>
new juicebox({
containerId: "juicebox-container",
baseUrl: "/People_gallery/",
galleryWidth: "100%",
galleryHeight: "100%",
backgroundColor: "#f1f1f1"
});
</script>
<div id="juicebox-container"></div>
<!--END JUICEBOX EMBED-->
As long as your gallery folder is named 'People_gallery' and is located in your web space's root directory, then it should display fine once the web page is uploaded to your web server.
For reference, the baseUrl method of embedding is documented here.
There is a note for Dreamweaver users here: Embedding Using Dreamweaver.