uploadHandler.php

<?php
function upload($file) {
	
	$allowed = array("image/png", "image/jpg", "image/jpeg", "image/gif");
	$type = $file['type'];
	$extension = end(explode("/", $type));
	$destination = sha1(time().rand().md5($file['name'])).".".$extension;
	$directory = "./uploads/";
	$limit = 1024000;
	$success = "Your photo has been uploaded!";
		
	if(!in_array($type, $allowed)) {
		$error = "The file you are trying to upload is not an allowed file type. Please upload only PNG's, JPEG's, or GIF's.";
	}
		
	if($file['size'] > $limit) {
		$error = "The photo you are uploading exceeds our maximum size of 1000KB. Please compress the photo or try uploading another one.";
	}
		
	if(!isset($error)) {
		move_uploaded_file($file['tmp_name'], $directory.$destination) or die("Cannot upload file.");
		echo $success;
	} else {
		echo $error;
	}
	
}

//USAGE -------------
/*

      upload($_FILES['photo']); <- this will verify the file.

*/
?>