Hits are the number of files that are requested from the server. This includes images, graphics, audio and video files, plus any other files, including the web page itself.
Page Views are the total number of times a page is viewed. This includes any files with extensions such as .html .htm .php etc.
So if you have a web page with 20 images on it and someone visits that page, there will be one page view and 21 hits.