http://www.facebook.com/sharer/sharer.php?u=http%3A%2F%2Fwww.google.com
How can I customize the text and image. It looks like Facebook pulled the docs.
What you are talking about is the preview image and text that Facebook extracts when you share a link. Facebook uses the Open Graph Protocol to get this data.
Essentially, all you'll have to do is place these og:meta tags on the URL that you want to share -
As you can see there are both an image property and a description. When you make changes to your pages og:meta tags, you can test these changes using the Facebook Debugger. It will tell you if you have made any mistakes (and how to fix them!)