I have modified the previous code for uploading images and creating the gallery automatically.

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The image upload interface will be displayed when we add the following code.I have named it as 'imageUpload.php'.

Note : to run this code we need to create the following file and folder structure

--imageUpload.php
--upload.php
--images(folder)
-----thumbnail(folder inside images)

Code : imageUpload.php
</code>

<html>
<head><title>Multiple Picture Upload</title>
</head><body>
<table border="0" cellspacing="3" cellpadding="15" align="center">
<tbody>
<form method="post" action="upload.php" enctype="multipart/form-data" name="form">
<tr>
<td><?php echo $change; ?> </td>
</tr>
<tr>
<td> <input size="25" name="file" type="file" /></td>
</tr>
<tr>
<td> <input size="25" name="file2" type="file" /></td>
</tr>
<tr>
<td> <input size="25" name="file3" type="file" /></td>
</tr>
<tr>
<td> <input size="25" name="file4" type="file" /></td>
</tr>
<tr>
<td> <input size="25" name="file5" type="file" /></td>
</tr>
<tr>
<td>Image maximum size&nbsp;&nbsp;<b>400 </b>&nbsp;&nbsp;kb</td>
</tr>
<tr>
<td><input type="submit" value="Upload" name="Submit"/></td>
</tr>
</tbody>
</form>
</table></body>
</html>

<code>



The uploading task will be done by the 'upload.php' file
Code : upload.php

</code>

<?php
error_reporting(0);
require_once('imageClass.php');

$change="";

//set the maximum size of the images can be uploaded
define ("MAX_SIZE","400");
function getExtension($str) {
$i = strrpos($str,".");
if (!$i) {
return "";
}
$l = strlen($str)-$i;
$ext = substr($str,$i,$l);
return $ext;
}

$errors=0;
if($_SERVER["REQUEST_METHOD"] == "POST") {
global $files;
$files = array('file','file2','file3','file4','file5');

for($m=0; $m<5; $m++ ) {

$file = $files[$m];

$image =$_FILES["$file"]["name"];
$uploadedfile = $_FILES["$file"]["tmp_name"];

if ($image) {
$filename = stripslashes($_FILES["$file"]["name"]);
$extension = getExtension($filename);
$extension = strtolower($extension);

if (($extension != ".jpg") && ($extension != ".jpeg") && ($extension != ".png") && ($extension != ".gif")) {

$change='<div>Unknown Image extension </div> ';
$errors=1;
}
else {
$size=filesize($_FILES["$file"]["tmp_name"]);
if ($size > MAX_SIZE*1024) {
$change='<div>You have exceeded the size limit!</div> ';
$errors=1;
}
else {

if($extension==".jpg" || $extension==".jpeg" ) {
$uploadedfile = $_FILES["$file"]["tmp_name"];
$src = imagecreatefromjpeg($uploadedfile);

}
else if($extension==".png") {
$uploadedfile = $_FILES["$file"]["tmp_name"];
$src = imagecreatefrompng($uploadedfile);
}
else if($extension==".gif") {
$src = imagecreatefromgif($uploadedfile);
}
else {
$src = imagecreatefromjpeg($uploadedfile);
}

list($width,$height)=getimagesize($uploadedfile);

$newwidth1=$width;
$newheight1=$height;
$tmp1=imagecreatetruecolor($newwidth1,$newheight1);

imagecopyresampled($tmp1,$src,0,0,0,0,$width,$height,$width,$height);

$filename1 = "images/". $_FILES["$file"]["name"];
if($extension == '.jpg' || $extension == '.jpeg') {
imagejpeg($tmp1,$filename1,100);
}
if($extension == '.png' ) {
imagepng($tmp1,$filename1,100);
}
if($extension == '.gif' ) {
imagegif($tmp1,$filename1,100);
}

$image = new Image();
$filename = "images/". $_FILES["$file"]["name"];
$info = pathinfo($filename1);
$imageName =  basename($filename,'.'.$info['extension']);
$image->load($filename);
$image->resize(100,100);
$image->save($imageName);

imagedestroy($src);
imagedestroy($tmp1);
}
}
}
}
}

header("location:gallery.php");

<code>



Here we have to create thumbnails.Image Class will do this stuff.
imageClass.php

</code>
<?php

class Image {

var $image;
var $image_type;

function load($filename) {
$image_info = getimagesize($filename);
if($image_info['mime'] == 'image/jpeg' ) {

$this->image_type = 'jpg';
$this->image = imagecreatefromjpeg($filename);
} elseif($image_info['mime'] == 'image/gif'  ) {
$this->image_type = 'gif';
$this->image = imagecreatefromgif($filename);
} elseif($image_info['mime']== 'image/png' ) {
$this->image_type = 'png';
$this->image = imagecreatefrompng($filename);
}
}
function save($filename, $compression=75) {
if( $this->image_type == 'jpg') {
imagejpeg($this->image,'images/thumbnail/thumb_'.$filename.'.'.$this->image_type,$compression);
} elseif( $this->image_type == 'gif' ) {
imagegif($this->image,'images/thumbnail/thumb_'.$filename.'.'.$this->image_type);
} elseif( $this->image_type == 'png') {
imagepng($this->image,'images/thumbnail/thumb_'.$filename.'.'.$this->image_type);
}
}

function resize($width,$height) {
$new_image = imagecreatetruecolor($width, $height);
imagecopyresampled($new_image,$this->image, 0, 0, 0, 0, $width, $height,imagesx($this->image),imagesy($this->image));
$this->image = $new_image;
}
}
<code>



Then we should create the gallery

Code : gallery.php

</code>

<html>
<head>
<style type="text/css">
img { border: 1px solid #000 }

#gallery img {
margin: 10px;
width: 85px;
height: 85px
}

#enlarge img {
width: 200px;
height: 200px;
}

</style>
</head>

<body>

<table>
<tr width="500">
<td width="45%" align="center">
<div id="enlarge">
<?php
$handle=opendir("images");

while (($file = readdir($handle))!==false) {
if(($file == '.' )|| ($file== '..') || ($file== 'thumbnail')) {
continue;
}
echo '<img name="LargeImage" src="images/';
echo $file;
echo '" />';
break;

}
?>

</div>
</td>

<td cellspacing=50>
<a href="imageUpload.php">Upload Images</a>
<div id="gallery">

<?php

// open the current directory by opendir
$handle=opendir("images");
$i == 2;
while (($file = readdir($handle))!==false) {

if(($file == '.' )|| ($file== '..') || ($file== 'thumbnail')) {
continue;

}
echo '<a href="#" onclick="LargeImage.src=';
echo "'images/$file'";
echo '"><img src="images/thumbnail/thumb_'.$file.'" /></a>';

}

closedir($handle);
?>

</div>
</td>
</tr>
</table>

</body>
</html>

<code>