I'm working on task of share a link on facebook. But I want to display my own static image (independent of url). With help of google and facebook, I come to know that I have to pass image path (which I want to display) in image parameter of sharer.php. But still, it displays image related to that site. I don't know that where is my mistake. If anyone know answer then please explain or suggest me link from where I can understand from beginning. Thank You. Here is my code.
<?php
$title = urlencode("How to Create a Custom Facebook Share Button with a Custom Counter");
$url = urlencode("http://www.daddydesign.com/wordpress/how-to-create-a-custom-facebook-share-button-with-a-custom-counter/");
$summary = urlencode("Learn how to create a custom Facebook 'Share' button, complete with a custom counter, for your website!");
$image = urlencode("http://www.daddydesign.com/ClientsTemp/Tutorials/custom-iframe-share-button/images/thumbnail.jpg");
?>
<html>
<a id="button" onClick="window.open('http://www.facebook.com/sharer.php?s=100&p[title]=<?php echo $title; ?>&p[summary]=<?php echo $summary; ?>&p[url]=<?php echo $url; ?>&&p[images][0]=<?php echo $image; ?>', 'sharer', 'toolbar=0,status=0,width=550,height=400');" target="_parent" href="javascript: void(0)">
Click to Share
</a>
</html>
Your image http://www.daddydesign.com/ClientsTemp/Tutorials/custom-iframe-share-button/images/thumbnail.jpg is the problem - it's not actually an image but takes you to a regular webpage.
You need to set a specific image which fits facebook's size requirements, the minimum size is 200x200 pixels.
来源：https://stackoverflow.com/questions/31753741/custom-image-on-facebook-sharer