<?php

//define a maxim size for the uploaded images in Kb

 define ("MAX_SIZE","100"); 

 

//This function reads the extension of the file. It is used to determine if the file  is an image by checking the extension.

 function getExtension($str) {

         $i = strrpos($str,".");

         if (!$i) { return ""; }

         $l = strlen($str) - $i;

         $ext = substr($str,$i+1,$l);

         return $ext;

 }

 

//This variable is used as a flag. The value is initialized with 0 (meaning no error  found)  

//and it will be changed to 1 if an errro occures.  

//If the error occures the file will not be uploaded.

 $errors=0;

//checks if the form has been submitted

 if(isset($_POST['Submit'])) 

 {

 	//reads the name of the file the user submitted for uploading

 	$image=$_FILES['image']['name'];

 	//if it is not empty

 	if ($image) 

 	{

 	//get the original name of the file from the clients machine

 		$filename = stripslashes($_FILES['image']['name']);

 	//get the extension of the file in a lower case format

  		$extension = getExtension($filename);

 		$extension = strtolower($extension);

 	//if it is not a known extension, we will suppose it is an error and will not  upload the file,  

	//otherwise we will do more tests

 if (($extension != "png") && ($extension != "png") && ($extension != "png") && ($extension != "png")) 

 		{

		//print error message

 			echo '<h1>Unknown extension!</h1>';

 			$errors=1;

 		}

 		else

 		{

//get the size of the image in bytes

 //$_FILES['image']['tmp_name'] is the temporary filename of the file

 //in which the uploaded file was stored on the server

 $size=filesize($_FILES['image']['tmp_name']);

 

//compare the size with the maxim size we defined and print error if bigger

if ($size > MAX_SIZE*1024)

{

	echo '<h1>You have exceeded the size limit!</h1>';

	$errors=1;

}

 

//we will give an unique name, for example the time in unix time format

$image_name=time().'.'.$extension;

//the new name will be containing the full path where will be stored (images folder)

$newname="images/".$image_name;

//we verify if the image has been uploaded, and print error instead

$copied = copy($_FILES['image']['tmp_name'], $newname);

if (!$copied) 

{

	echo '<h1>Copy unsuccessfull!</h1>';

	$errors=1;

}}}}

 

//If no errors registred, print the success message

 if(isset($_POST['Submit']) && !$errors) 

 {

 	echo "<h1>File Uploaded Successfully! Try again!</h1>";

 }

 

 ?>

 

 <!--next comes the form, you must set the enctype to "multipart/frm-data" and use an input type "file" -->

 <form name="newad" method="post" enctype="multipart/form-data"  action="">

 <table>

 	<tr><td><input type="file" name="image"></td></tr>

 	<tr><td><input name="Submit" type="submit" value="Upload image"></td></tr>

 </table>	

 </form>