WordPress at a glance
function is not described

file_is_valid_image() WP 2.5.0

Validate that file is an image.

No Hooks.

Return

true/false. True if valid image, false if not valid image.

Usage

file_is_valid_image( $path );
$path(string) (required)
File path to test if valid image.

Code of file is valid image: wp-admin/includes/image.php VER 5.0.3

<?php
function file_is_valid_image($path) {
	$size = @getimagesize($path);
	return !empty($size);
}