When you go to a category with subcategories, the 'recent images' function shows images from all categories, while it would be more logical and intuitive if it would show latest images from that particular category.
When you go to a category without subcategories, the category menu completely disappears. This behavior comes across as confusing. The user expects a navigation to be present there.
I would like to suggest, to add a treeview Jquery tree menu
for categories. This would enhance the look and feel of PP Pro and should be simple to add.