get extension from filename php

$ext = pathinfo($filename, PATHINFO_EXTENSION);

// Here is a quick way of fetching only the filename (without extension) regardless of what suffix the file has.

// your file
$file = 'image.jpg';
$info = pathinfo($file);
// Before PHP 5.2
$file_name =  basename($file, '.'.$info['extension']);
// After PHP 5.2
$file_name =  $info['filename'];

pathinfo($path, PATHINFO_FILENAME);