Hi there,
with a minor tweak the plugin gets compatible with WP 2.x - simply change Line 34 into:
if (function_exists("has_post_thumbnail") && has_post_thumbnail($post->ID)) {
Another tweak can be used to add Open Graph support - just add in Line 58:
echo '<meta property="og:image" content="' . esc_attr($image) . '"/>';
Best regards,
Hendrik
http://wordpress.org/extend/plugins/fetenweb-image-src-metatag/