Thumbnail generating script for png,jpg,jpeg,gif for old & new versions of php

In this post  Iam explaining about a thumbnail generator script which can be used in your site. This script can be used to make thumbnails of jpeg,png & gif images. You can reduce to any thumbnail size that you prefer.
For doing it, Just copy the below code and name it as thumb.php. save this file in your project folder.
For generating thumb nail, you just want to do like this :-
 <img src="thumb.php?file=your_file_path&size=your_size">
For eg:
<img src="thumb.php?file=image.jpg&size=100">


<?php
ini_set('memory_limit','64M');
$site_config['document_root'] = $_SERVER['DOCUMENT_ROOT'];
$thumb_size = 128; //all thumbnails are this maximum width or height if not specified via get
$site_config['absolute_uri']=str_replace('///','//',str_replace('thumb.php?'.$_SERVER['QUERY_STRING'],'',$_SERVER['REQUEST_URI']));
$site_config['path_thumbnail']=$site_config['absolute_uri'].'/cache/images/';    //where to cache thumbnails on the server, relative to the DOCUMENT_ROOT
$image_error=$site_config['document_root'].$site_config['absolute_uri'].'/images/icons/image_error.png';    // used if no image could be found, or a gif image is specified

$thumb_size_x = 0;
$thumb_size_y = 0;

# Define quality of image
if (@$_GET["quality"]<>0) {
    $quality    = $_GET["quality"];
} else {
    $quality    = 80;
}

# Define size of image (maximum width or height)- if specified via get.
if (@$_GET["size"]<>0) {
    $thumb_size=intval($_GET["size"]);
}
if (intval(@$_GET["sizex"])>0)
{
    $thumb_size_x=intval($_GET["sizex"]);
    if (intval(@$_GET["sizey"])>0)
    {
        $thumb_size_y=intval($_GET["sizey"]);
    } else {
        $thumb_size_y=$thumb_size_x;
    }
}

if (file_exists($_GET['file']))
{
    $filename=$_GET['file'];
} else {
    $filename=str_replace('//','/',$site_config['document_root'].$site_config['absolute_uri'].'/'.$_GET["file"]);
}

# If calling an external image, remove document_root
if (substr_count($filename, "http://")>0)

{
    $filename=str_replace($site_config['document_root'].$site_config['absolute_uri'].'/','',$filename);
}

$filename=str_replace("\'","'",$filename);
$filename=rtrim($filename);
$filename=str_replace("//","/",$filename);
$fileextension=substr($filename, strrpos ($filename, ".") + 1);

$cache_file=str_replace('//','/',$site_config['document_root'].$site_config['path_thumbnail'].md5($filename.@$thumb_size.@$thumb_size_x.@$thumb_size_y.@$quality).'.'.$fileextension);

# remove cache thumbnail?
if (@$_GET['nocache']==1)
{
    if (file_exists($cache_file))
    {
        #remove the cached thumbnail
        unlink($cache_file);
    }
}

if ((file_exists($cache_file)) && (@filemtime($cache_file)>@filemtime($filename)))
{
    header('Content-type: image/'.$fileextension);
    header("Expires: Mon, 26 Jul 2030 05:00:00 GMT");   
    header('Content-Disposition: inline; filename='.str_replace('/','',md5($filename.$thumb_size.$thumb_size_x.$thumb_size_y.$quality).'.'.$fileextension));
    echo (join('', file( $cache_file )));
    exit; # no need to create thumbnail - it already exists in the cache
}

# determine php and gd versions
$ver=intval(str_replace(".","",phpversion()));
if ($ver>=430)
{
    $gd_version=@gd_info();
}

# define the right function for the right image types
if (!$image_type_arr = @getimagesize($filename))
{
    header('Content-type: image/png');
    if(@$_GET['noerror'])
    {
        exit;
    } else {   
        echo (join('', file( $site_config['document_root'].$image_error )));
        exit;
    }
}
$image_type=$image_type_arr[2];

switch ($image_type)
{
    case 2: # JPG
        if (!$image = @imagecreatefromjpeg ($filename))
        {
            # not a valid jpeg file
            $image = imagecreatefrompng ($image_error);
            $file_type="png";
            if (file_exists($cache_file))
            {
                # remove the cached thumbnail
                unlink($cache_file);
            }
        }
        break;

    case 3: # PNG
        if (!$image = @imagecreatefrompng ($filename))
        {
            # not a valid png file
            $image = imagecreatefrompng ($image_error);
            $file_type="png";           
            if (file_exists($cache_file))
            {
                # remove the cached thumbnail
                unlink($cache_file);
            }
        }           
        break;

    case 1: # GIF
        if (!$image = @imagecreatefromgif ($filename))
        {
            # not a valid gif file
            $image = imagecreatefrompng ($image_error);
            $file_type="png";           
            if (file_exists($cache_file))
            {
                # remove the cached thumbnail
                unlink($cache_file);
            }
        }           
        break;
    default:
        $image = imagecreatefrompng($image_error);
        break;

}

# define size of original image   
$image_width = imagesx($image);
$image_height = imagesy($image);

# define size of the thumbnail   
if (@$thumb_size_x>0)
{
    # define images x AND y
    $thumb_width = $thumb_size_x;
    $factor = $image_width/$thumb_size_x;
    $thumb_height = intval($image_height / $factor);
    if ($thumb_height>$thumb_size_y)
    {
        $thumb_height = $thumb_size_y;
        $factor = $image_height/$thumb_size_y;
        $thumb_width = intval($image_width / $factor);
    }       
} else {
    # define images x OR y
    $thumb_width = $thumb_size;
    $factor = $image_width/$thumb_size;
    $thumb_height = intval($image_height / $factor);
    if ($thumb_height>$thumb_size)
    {
        $thumb_height = $thumb_size;
        $factor = $image_height/$thumb_size;
        $thumb_width = intval($image_width / $factor);
    }
}

# create the thumbnail
if ($image_width < 4000)    //no point in resampling images larger than 4000 pixels wide - too much server processing overhead - a resize is more economical
{
    if (substr_count(strtolower($gd_version['GD Version']), "2.")>0)
    {
        //GD 2.0
        $thumbnail = ImageCreateTrueColor($thumb_width, $thumb_height);
           $white = imagecolorallocate($thumbnail, 255, 255, 255);
   
        imagefilledrectangle($thumbnail, 0, 0,$thumb_width, $thumb_height, $white);
        imagecopyresampled($thumbnail, $image, 0, 0, 0, 0, $thumb_width, $thumb_height, $image_width, $image_height);
    } else {
        //GD 1.0
        $thumbnail = imagecreate($thumb_width, $thumb_height);
                   $white = imagecolorallocate($thumbnail, 255, 255, 255);
   
        imagefilledrectangle($thumbnail, 0, 0, $thumb_width, $thumb_height, $white);
        imagecopyresized($thumbnail, $image, 0, 0, 0, 0, $thumb_width, $thumb_height, $image_width, $image_height);           
    }   
} else {
    if (substr_count(strtolower($gd_version['GD Version']), "2.")>0)
    {
        # GD 2.0
        $thumbnail = ImageCreateTrueColor($thumb_width, $thumb_height);
                   $white = imagecolorallocate($thumbnail, 255, 255, 255);
   
        imagefilledrectangle($thumbnail, 0, 0, $thumb_width, $thumb_height, $white);
        imagecopyresized($thumbnail, $image, 0, 0, 0, 0, $thumb_width, $thumb_height, $image_width, $image_height);
    } else {
        # GD 1.0
        $thumbnail = imagecreate($thumb_width, $thumb_height);
                   $white = imagecolorallocate($thumbnail, 255, 255, 255);
   
        imagefilledrectangle($thumbnail, 0, 0,$thumb_width, $thumb_height, $white);
        imagecopyresized($thumbnail, $image, 0, 0, 0, 0, $thumb_width, $thumb_height, $image_width, $image_height);
    }
}

# insert string
if (@$_GET['tag']<>"")
{
    $font=1;
    $string= $_GET['tag'];
    $white = imagecolorallocate ($thumbnail, 255, 255, 255);
    $black = imagecolorallocate ($thumbnail, 0, 0, 0);
    imagestring ($thumbnail, $font, 3, $thumb_height-9, $string, $white);
    imagestring ($thumbnail, $font, 2, $thumb_height-10, $string, $white);
}

switch ($image_type)
{
    case 2:    # JPG
        header('Content-type: image/jpeg');
        header('Content-Disposition: inline; filename='.str_replace('/','',md5($filename.$thumb_size.$thumb_size_x.$thumb_size_y.$quality).'.jpeg'));
        @imagejpeg($thumbnail,$cache_file, $quality);
        imagejpeg($thumbnail,NULL,$quality);

        break;
    case 3: # PNG
        header('Content-type: image/png');
        header('Content-Disposition: inline; filename='.str_replace('/','',md5($filename.$thumb_size.$thumb_size_x.$thumb_size_y.$quality).'.png'));
        @imagepng($thumbnail,$cache_file);
        imagepng($thumbnail);
        break;

    case 1:    # GIF
        if (function_exists('imagegif'))
        {
            header('Content-type: image/gif');
            header('Content-Disposition: inline; filename='.str_replace('/','',md5($filename.$thumb_size.$thumb_size_x.$thumb_size_y.$quality).'.gif'));
            @imagegif($thumbnail,$cache_file);
            imagegif($thumbnail); 
        } else {
            header('Content-type: image/jpeg');
            header('Content-Disposition: inline; filename='.str_replace('/','',md5($filename.$thumb_size.$thumb_size_x.$thumb_size_y.$quality).'.jpg'));
            @imagejpeg($thumbnail,$cache_file);
            imagejpeg($thumbnail);
        }
        break;
}

//clear memory
imagedestroy ($image);
imagedestroy ($thumbnail);

?>