This is a question you can read everywhere on the web with various answers:
$ext = end(explode(\'.\', $filename)); $ext = substr(strrchr($filename, \'.\'), 1
As long as it does not contain a path you can also use:
array_pop(explode('.', $fname))
Where $fname is a name of the file, for example: my_picture.jpg. And the outcome would be: jpg
$fname
my_picture.jpg
jpg