How can i show the images outside the web root directory in my php application?

PHP by default can already access files outside the web root, unless restricted with an open_basedir directive (or safe mode, but hope you're not in that cage).

It's normally a good practice to insert within a VirtualHost configuration an open_basedir restriction. You can specify multiple directories separated by : on Linux and ; on windows.

php_admin_value open_basedir /var/www/s/stage:/usr/share/php:/your/dir

To access those files either use an absolute path or a path relative to the position of the PHP file called. (So you'll have to ../ to reach levels above).

Also be sure that directories in which you want to write to are assigned to the webserver user and have write permission.

Otherwise you have second option:

Inside your www directory, create a "image.php" file, with a similar content to:

<?php
  header('Content-Type: image/png');
  readfile("../img/" . $_GET['img']);
?>

And call your images with

<img src="image.php?img=myimage.png" />

Please be aware that your PHP file shouldn't be that simple :) As you may want to address multiple image formats (and providing the correct header for them), checking for malicious file path/inclusions (you don't want to use $_GET without validating/sanitizing the input), extra caching etc. etc. etc.

But this should give you an idea on how you can target your issue.

As simple as that, this will output the image with correct headers,
remember that you have to set the header() before flushing anything out of the output buffer
=> no echo or print before

$file = '../../somedirectory/image.jpg';
header('Content-Type:image/jpeg');
header('Content-Length: '.filesize($file));
echo file_get_contents($file);

For my application, none of those answers were working - I simply couldn't get the image to display and it wasn't really feasible for me to add a new php file to call because reasons. What DID work for me is

$filename = read_filename_from_database;
$fileDir = "/path/to/files/";
$file = $fileDir . $filename;
if (file_exists($file))
{
     $b64image = base64_encode(file_get_contents($file));
     echo "<img src = 'data:image/png;base64,$b64image'>";
}