I have followed an example of Facebook share by using URL and parameters
Original (working)
Fiddle >> http://jsfiddle.net/dYfwK/
<a href="http://www.facebook.com/sharer.php?s= 100&p[title]=Title here&p[url]=http://example.com&p[images][0]=http://upload.wikimedia.org/wikipedia/commons/5/55/Kaasmarkt2_close.jpg&p[summary]=I love cheese" target="_blank">Test</a>
Modified (image not appearing)
Fiddle >> http://jsfiddle.net/dYfwK/6/
<a href="http://www.facebook.com/sharer.php?s= 100&p[title]=Title here&p[url]=http://example.com&p[images]
[0]=http://www.ucmas.com/wp-content/uploads/2013/07/rm.jpg&p[summary]=I love cheese" target="_blank">Test</a>
I've been facing this issue for sometime, eventually I believe this issue is due to the image. Is it the size or something else that caused this ?
When I do this it works:
<a href="https://www.facebook.com/sharer.php?s=100&p[title]=Title+here&p[url]=http://example.com&p[summary]=I+love+cheese&p[images][0]=http://www.ucmas.com/wp-content/uploads/2013/07/rm.jpg" target="_blank">Test</a>
What you need to do is remove & from the url and replace it with real &. I then url encoded everything that wasnt a link. this just means replace spaces with +. I also put image at the end of the url. Not sure why but that seemed to do the trick.