Does Adsense actually have requirements for websites that make it in in terms of volume of content, or any of that?
To get approved, you need to make the site that has original contents with certain amount of volume of content, not only just a few sentences and full of pictures. I think google loves content (texts). You should fill your site with enough volume of text (original content) for google and also a few pictures for your visitors.
Volume is not a requirement for getting into adsense, you just need a site with informative, preferably original content.