Its not entirely complex if you have a little knowledge of php and mysql. Mysql is a database. This is where you would store such information as your client login information, a listing of the locations of your clients photos and even which ones that they've selected. As far as step by step instructions, that would take longer than for me to write the code . If you really want to learn php, you could start by creating a page, create a database and see if you can insert into it and select data out of it and display it. Once you get an understanding of how php and mysql work together, it'll be much easier for you to create your script.