Is there any built in function to render image file extension like jpg, png etc? Is there any built in function in Drupal 7 to render image file extension like jpg, png etc on node load.

I have tried image_get_info etc.
image_get_info() should do the trick.

//if you want to get the extension of image1.jpg
$filepath = "sites/default/files/images/image1.jpg";
$info_var = image_get_info($filepath, FALSE);
echo "the image extension is ".$info_var['extension'];