This is a great extension, and keeps getting better! The quality of the phocagallery component is great and very stable.
For the features backlog, I would like to see a field added to the "Categories" admin menu, such that when editing a Category, I could select the photo used as the Category thumbnail. (Alternately, a flag "Use as Category Thumbnail" on a specific image, though I expect this alternative is harder to implement being this is related to the categories display.)
Most of my photo categories are fine, so this isn't a general parameter setting solution. But I do have one catalog with over 1,500 photos (four different cameras!) from a wedding, and I'd like to select a specific photo from within this category for the category thumbnail. The images are posted in a chronological order of events from the day, and sorting the category by hand with so many photos is nearly impossible.