Help with photo gallery idea!

I've want to create a few gallery pages, all the page will contain is
a table with with 12 cells that hold the thumbnails, once clicked the
image will open in a pop up. This isn't a problem, but what i want to
do is use some form of script that will update the images when new
one's are added to the image folder. I have no idea of how to do this
or not really a clue where to start looking.

for a better idea of what i mean...

http://www.goffskitchen.co.uk/PhoneCam/CamIndex.html

thanks.