Wonderful Idea that could help alot of deviants out. I like the concept of being able to add info for a user to have access to when they first visit your gallery. You mentioned the compromise of having to have the text on one side and folder links on the oppiste and I think that makes since and doesent seem like a downside besides shrinking the width for thumbs.
From what I see it appears you created a new folder and named it featured in order to make part of this and then edited it with a screenshot of the actual featured page. while it makes it look real It leaves out a few things, for one you dont see how the page would look with the folders added, also their is no edit button shown which would be neccesary for adding the description.
overall great concept would love to see it implemented but the suggestion does not show a perfect or practical model of how it would look if put in place.