Drupal 7 Tutorial: Image Fields
One of the more popular yet tricky things to do on a content management system is to attach images to content. It's tricky for two reasons. First, you have to upload a file from your local computer to the server via web browser. Second, for many scenarios your going to want to enforce some standard image formatting such as consistent image sizes. Well Drupal not only gives you the ability to upload images but has a rather clever way of automating cropping and other special formatting so they look uniform when displayed.