I agree that this is a good first start. In my experience, students and instructors often want to view more than one description at a time. They also need to be able to mouse-away from the description and still see it.
My instructor has posted 10 images in a folder, each with a description. I need to decide which one to use for my project based on the descriptive text. I really want to compare my favorite three directly, but can't find a way to view more than one description at once.
My instructor has used the description to post very specific directions about how to manipulate the image I've selected for my project. I need to manipulate it in Photoshop, but every time I move my mouse away from the floating description field, the description disappears.
Another option might be for the instructor to evoke an Option to show/hide list columns she deemed critical for her students. I've visited a million sites, for instance, where the Access column is completely filled down with "Entire Site," the Created By column completely filled down with the instructor's name, and the Modified column all set to the first week in September.
Perhaps the instructor could opt to hide these three columns (and I'd throw size in there too-- size does not always matter) and display the description by default, kind of like she has options to show the message or not in the Recent Announcements and also Announcements list. Or, a dropdown View option for the user. Besides the slick "I" icons, they might select "Title and Description" view to get a persistent, multi-description view.