Thanks for the suggestion. I had actually copied the whole folder from my computer onto the tablet, and it was classifying the folders as "albums" without showing the titles.
I found a free app to organize my tablet storage: the Astro File Manager. It classifies my stored files by type, i.e. books, movies, music, pictures. Now my titles (or at least the first part of the titles) are apparent with the thumbnail.
I thought I'd share in case someone else could use this.