Attaching any unattached media files that you may have floating around is a good way to keep things organized and running smooth. Normally, when you're working on a post in the Edit Post screen, you click the Upload/Insert button and use the nifty drag-n-drop media uploader to get 'er done. When you upload your media files in this manner, WordPress "knows" that you want to attach the file to that particular post. Super straightforward sure, but there are situations where WordPress doesn't know which post to use. In this DigWP post, we walk through the process of finding unattached media files and attaching them to their respective posts.
Recently, I found myself on the front lines of WordPress’ somewhat complicated Media-Library system. The site that I was developing required a rather elaborate system of retrieving and displaying image attachments. So, using the latest version of WordPress (2.8.3 at the time), I found myself experimenting with as many template tags and custom functions as I could find. After much experimentation, I discovered the perfect solution, and along the way I collected a healthy collection of recipes for displaying image attachments and their various types of associated information.