hmm… PHP is a good answer, and probably the one that will offer the most flexibility.
You could load array from variables in a text file, that way, the array is dynamic, so you can leave your swf alone. When you add pics to the folder, add some values to the txt file and have flash build the array from the items in the text file. Otherwise, if you want to be totally dynamic, build your MySQL database where you will put your pics, insert new pictures with php/html front end, this will automatically assign the new pic a new name in sequence (lastnameused+1). Then, have php build the array for you and feed it to flash.
That is about as dynamic as you can get…
you may still have to take the pictures yourself! ahahahahahaah
just kidding, dude.