How to question - Paging through images in a directory?

Hello, I have what I think is a simple problem, but I have been away from PHP for years, so I’m having a hard time. It’s a simple scenario. I have a comic short story. In a directory is a series of 20 images, and I have one page template, that has previous and next buttons.

In the directory, the images are numbered 01-20.

All I want to do is have the previous and next buttons “navigate” to the next image. In other words, reload the page with the next/previous image.

How would I go about doing this?

You could use the HTTP GET method, and use the ‘previous’ image link to -1 from the current number in the query string of the URI (provided it is greater than 1), or +1 to the query string in the URI for a ‘next’ image link to go to the next image (provided the number is less than 20). You can then build the image link from the HTTP GET variable. Something like the following:


if(isset($_GET['img_id'])) {
	$id = intval($_GET['img_id']);
	if($id < 1 || $id > 20) {
		$id = 1;
	$id = 1;

$currentImage = sprintf('images/%02s.jpg', $id);
<!DOCTYPE html>

<!-- output $currentImage -->

if($id > 1) {
	$previousImage = 'page.php?img_id='.($id-1);
	// output previous image link

if($id < 20) {
	$nextImage = 'page.php?img_id='.($id+1);
	// output next image link

You then just check to see if the variables $previousImage and $nextImage are set within the html body - if so, then the user can navigate using the previous and next links.

EDIT: I updated the $currentImage variable expression to cater for the extra 0 you have in front of the image names that are from 1-9