For web content, it is very important to have a diversity of content.
While it is good to have a site that is filled with text only, many sites often put images into their sites so that it could not only keep people interested, but also give them a better idea as to what they are reading about. Even certain videos can drive the point further home for users that are visiting your site.
For instance, if you are talking about a movie, you could display images from the movie provided you have permission for that.
You could also show clips from the movie. The key point is to get people interested and even excited for the movie that you are promoting. That way, they can buy the product from the original owners of the product. A diversity of content goes a long way towards promotion and sales.