How To Add Watermark To An Image with PHP and Imagepng

Hey!

Now I'm going to teach you how to add a watermark to an image.
It is really easy.

It does like this:

First lets define our image where we want our watermark:

$image = 'path/to/a/file.jpg';
 

Now we need to check what kind of image is it and set it up for processing:

if(eregi('.jpg', $image)) {
    
    $i = imagecreatefromjpeg($image);
    
}elseif(eregi('.gif', $image)) {
    
    $i = imagecreatefromgif($image);
    
}elseif(eregi('.png', $image)) {
    
    $i = imagecreatefrompng($image);
    
}

Now let's take our watermark:

$watermark = imagecreatefromgif('watermark.gif');
 

Next is taking width and height of our image and our watermark:

$width = imagesx($i);
$height = imagesy($i);
$watermark_width = imagesx($watermark);
$watermark_height = imagesy($watermark);
 

And now is the time for the most important step, putting those images together:

imagecopymerge($i, $watermark, (($width - $watermark_width)), (($height - $watermark_height)), 0, 0, $watermark_width, $watermark_height, 50);
 

If it's done, then we want to display our watermarked image:

if(eregi('.jpg', $image)) {
    
    header('Content-Type: image/jpeg');
    imagejpeg($i);
    
}elseif(eregi('.gif', $image)) {
    
    header('Content-Type: image/gif');
    imagegif($i);
    
}elseif(eregi('.png', $image)) {
    
    header('Content-Type: image/png');
    imagepng($i);
    
}

Now when everything is done, let's destroy our images:

imagedestroy($i);
imagedestroy($watermark);
 

And we are done!

If everything went well it should look like this:

Here's the full code:

<?php

/**
 * @author Jaan
 * @link http://webhostingtalkforums.com
 * @copyright 2011
 */

$image = 'battlefield.jpg';

if(eregi('.jpg', $image)) {
    
    $i = imagecreatefromjpeg($image);
    
}elseif(eregi('.gif', $image)) {
    
    $i = imagecreatefromgif($image);
    
}elseif(eregi('.png', $image)) {
    
    $i = imagecreatefrompng($image);
    
}

$watermark = imagecreatefromgif('watermark.gif');

$width = imagesx($i);
$height = imagesy($i);
$watermark_width = imagesx($watermark);
$watermark_height = imagesy($watermark);
imagecopymerge($i, $watermark, (($width - $watermark_width)), (($height - $watermark_height)), 0, 0, $watermark_width, $watermark_height, 50);


if(eregi('.jpg', $image)) {
    
    header('Content-Type: image/jpeg');
    imagejpeg($i);
    
}elseif(eregi('.gif', $image)) {
    
    header('Content-Type: image/gif');
    imagegif($i);
    
}elseif(eregi('.png', $image)) {
    
    header('Content-Type: image/png');
    imagepng($i);
    
}

imagedestroy($i);
imagedestroy($watermark);

?>
 