435688 PHP Script Modification

Hi have a custom php photo gallery that needs an option added to it. Right now this gallery sorts the pictures from newest to oldest. However. I need be able to arrange them in any order that I wish. I would like a drop down field on the add and edit photo pages in the admin that would allow us to make the photo appear where ever we want in the list on the site's photo gallery page. An important note is that this photo gallery uses categories. So When I am in the process of adding a new photo and select which category I want to put the photo in, below that will be this new drop down that allows the photo to be placed at the top, below photo 1, below photo 2 ect.. When I say "photo 1" I mean whatever the title for the photo is. This is how we determine what photos are in the admin is by the title of them. It's Important that when I select a category that the new sort drop down only shows the photos in that category NOT all photos. I want someone who knows what they are doing and preferable someone who uses msn messenger is possible.