facebook opengraph, i hate it. (: please help

I would like to make it so when a user clicks Like, a specified image is used for that specific post/page.

Which would be defined by a custom field “og_custom_image”

if there is not a specified custom field containing the image for that specific post/page then i want a default image to kick in and take its place.

So far:

Im using Thesis Theme, and i have added this

http://diythemes.com/thesis/rtfm/facebook-open-graph-meta-tags/

i then modified the

og:image thingy to

<meta property=”og:image” content=”<?php echo $image = get_post_meta($post->ID, ‘og_custom_image’, $single = true); ?>” />

i then tested to see if a default image would appear and instead a random picture on the page was used instead.

in the code from the link above, i did

$image = ‘ENTER URL TO DEFAULT IMAGE HERE’;

i placed my default url there.. but nothing.. still uses same image..

im aware that facebook caches things, so what i did was each time i tested it, was from a different post/url .

why are things so hard for me.. lol