Below GIF image is an example image which can contain real-time data. A PHP script calculates the pending time till new year and generates the GIF image. An ideal solution for sending e-mails with real-time data to customers. E-mail clients give you the opportunity to load images by URL and so everytime the client re-opens the e-mail message, the GIF will be re-generated with real-time data.

For below image this doesn't work, unfortunately, because GitHub downloads the image once and stores it locally. Most e-mail clients, however, do load the images directly from source. Successfully tested with Gmail and Outlook 2011 (Mac OSX).

Important note: Outlook 2007, 2010 and 2013 for Windows will only show the first frame. More information about this, coming soon! TIP!: Keep the first frame universal, so it doesn't matter the GIF image animates or not.

##Note I received some questions about Gmail so lets describe this mail client a bit more in detail. This script is successfully tested with Gmail, at the moment of writing, which is 2015-12-23. Gmail loads the images via their own proxy, so not directly from source. There are different opinions about the proxy, but it seems that Google's proxy protects your private data and only informs the sender that the email has been opened. There are speculations that Gmail caches the images, but still respect the cache headers, so you can instruct Gmail how often to refresh the data. I personally had no trouble with the cache whatsoever! I've tested this countdown image numerous times in Gmail and of course you can test it yourself as well. Just to be sure I've added some cache disabling headers in the examples.

##Getting Started

Create a PHP file and add these headers at the beginning of the file:

// Caching disable headers
header("Cache-Control: no-store, no-cache, must-revalidate, max-age=0");
header("Cache-Control: post-check=0, pre-check=0", false);
header("Pragma: no-cache");

// Output as a GIF image
header ('Content-type:image/gif');

// Include the GIFGenerator class
include('GIFGenerator.class.php');

On the next lines you can create a GIF image by first initializing the GIFGenerator object and creating an array with all the image frames:

// Initialize a new GIFGenerator object
$gif = new GIFGenerator();

// Create a multidimensional array with all the image frames
$imageFrames = array(
	'repeat' => false,
	'frames' => array(
		array(
			'image' => './images/newyear.jpg',
			'text' => array(
				array(
					'text' => 'Hello GIF frame 1',
					'font-color' => '#000',
					'x-position' => 140,
					'y-position' => 138
				)
			),
			'delay' => 100
		),
	)
);

Finally you generate the image and echo the results on the screen:

echo $gif->generate($imageFrames);

##Example

A more complete example. You could copy/paste below code to a file and execute it in the browser to view a more complete result. As you can see it's not required to use text in your GIF image and you can add as much text per frame, and as much frames per GIF image as you like.

<?php
// Caching disable headers
header("Cache-Control: no-store, no-cache, must-revalidate, max-age=0");
header("Cache-Control: post-check=0, pre-check=0", false);
header("Pragma: no-cache");

// Output as a GIF image
header ('Content-type:image/gif');

// Include the GIFGenerator class
include('GIFGenerator.class.php');

// Initialize a new GIFGenerator object
$gif = new GIFGenerator();

// Create a multidimensional array with all the image frames
$imageFrames = array(
	'repeat' => 5,
	'frames' => array(
		array(
			'image' => './images/newyear.jpg',
			'text' => array(
				array(
					'text' => 'Hello GIF frame 1',
					'font' => './fonts/Lato-Light.ttf',
					'font-size' => 30,
					'angle' => 0,
					'font-color' => '#000',
					'x-position' => 140,
					'y-position' => 138
				)
			),
			'delay' => 100
		),
		array(
			'image' => './images/newyear.jpg',
			'text' => array(
				array(
					'text' => 'Hello GIF frame 2',
					'font' => './fonts/Lato-Light.ttf',
					'font-size' => 15,
					'angle' => 0,
					'font-color' => '#000',
					'x-position' => 140,
					'y-position' => 138
				),
				array(
					'text' => 'Hello GIF frame 2',
					'font' => './fonts/Lato-Light.ttf',
					'font-size' => 15,
					'angle' => 0,
					'font-color' => '#000',
					'x-position' => 140,
					'y-position' => 108
				)
			),
			'delay' => 100
		),
		array(
			'image' => './images/newyear.jpg',
			'delay' => 50
		)
	)
);

echo $gif->generate($imageFrames);
?>

##License & Credits

This software is published under the MIT License.

######GIFEncoder

GIFEncoder.class.php contains minor adaptations from the GIFEncoder PHP class by László Zsidi.