Not able to download a file in php. Filename passed through url - php

Question

I am just a beginner with PHP. I am trying to download an image file when a url is clicked.
When I hardcode the filename it works, however when I try to download different image files based on the url clicked, it does not work. The code might explain it in a better way.
Code when a url is clicked
Download brochure
download.php
<?php
$var=$_GET['var'];
$filename=$var;
$filename = './img/Photo6.jpg'; // this works
//$filename = $var; // this does not work
header('Pragma: public');
header('Expires: 0');
header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
header('Cache-Control: private', false); // required for certain browsers
header('Content-Type: image/jpeg');
header('Content-Disposition: attachment; filename="'. basename($filename) . '";');
header('Content-Transfer-Encoding: binary');
header('Content-Length: ' . filesize($filename));
readfile($filename);
exit;
?>
Kindly help.
Thanks.

Answer 1

when you use:
$_GET['var'];
You are expecting a url construct with an ? inside it:
./download.php?var=./img/Photo6.jpg
in your sample: var=./img/Photo6.jpg, tells to php the variable GET[var] will take the value ./img/Photo6.jpg
so, your different image files based on the url clicked, must have the
./download.php?var=XXX
structure to work. Be sure all your urls has that structure.