Are you using sessions? If so, read the pictures names into an array the first time the user comes to the site.
mypictures[] = "pict.jpg";
mypictures[] = "pict2.jpg";
Pass mypicture through all the pages. Decide how many pictures you want per page. Divide the number of elements in the array --- using count() --- by the number of pictures you want per page. Then you can figure out how many pages you have. Print out the number of pages dynamically with links....
<a href='page.php?page=1'>1</a>
<a href='page.php?page=2'>2</a>
If page=2, and you know you have 6 pictures per page then you know to start at image number 7 (mypictures[7]) and then show the next 6 pictures.
Drew