Hi, I am creating a theme for ZenPhoto for my personal use on my website. I would like to add function to display "Sort Images" Options in Album Page in my Theme.

Sort Options (Oldest - File Name - Top Rated - Newest)

Is there any function to display such option?

Sorry, there is no such function. And there not directly a sortorder for "popular" items at all. You would have to do some custom coding to achieve this.