By general, I insert only the name of an image. I save the images in a folder.
Anyway, sure that you can do so. There are some tutorials talking about that. You will have to do output buffering to display the mime content stored in the mysql record with header function or ob_start (depending if the headers are already sent).
Look at the [URL="http://www.onlamp.com/pub/a/onlamp/2002/05/09/webdb2.html"]ONLamp[/URL] tutorial.