There are a couple of places where additional functionalty could be implemented. For example, being able to include more than 1 gallery in a single article and, having the ability to propagate the same snippet of picture description across multiple pictures at a single go. But, I'm sure that the author is aware of the areas that would make this extension even better than it already is.
However, what really impressed me was that I had a problem with a program error and the author got back to me promptly with the solution. This shows where the small outfit can really beat the billion dollar multinationals hands down.