Index: vimeo_link_formatter.module
===================================================================
--- vimeo_link_formatter.module	(revision 20)
+++ vimeo_link_formatter.module	(working copy)
@@ -18,12 +18,12 @@
     'settings' => vimeo_link_formatter_default_settings_player(),
   );
 
-  // @todo Implement the rest of this.
-  // $formatters['vimeo_link_formatter_thumbnail'] = array(
-  //   'label' => t('Vimeo Thumbnail'),
-  //   'description' => t('Displays the thumbnail of Vimeo video, if the URL is for a Vimeo.com video page.'),
-  //   'field types' => array('link_field'),
-  // );
+  $formatters['vimeo_link_formatter_thumbnail'] = array(
+     'label' => t('Vimeo Thumbnail'),
+     'description' => t('Displays the thumbnail of Vimeo video, if the URL is for a Vimeo.com video page.'),
+     'field types' => array('link_field'),
+     'settings' => vimeo_link_formatter_default_settings_thumbnail(),
+  );
 
   return $formatters;
 }
@@ -35,6 +35,7 @@
   module_load_include('admin.inc', 'vimeo_link_formatter');
   // Call the function which handles this formatter.
   $function = __FUNCTION__ . '_' . $instance['display'][$view_mode]['type'];
+
   return call_user_func($function, $field, $instance, $view_mode);
 }
 
@@ -54,6 +55,7 @@
 function vimeo_link_formatter_field_formatter_view(&$entity_type, &$entity, &$field, &$instance, &$langcode, &$items, &$display) {
   // Call the function which handles this formatter.
   $function = __FUNCTION__ . '_' . $display['type'];
+  
   return call_user_func($function, $entity_type, $entity, $field, $instance, $langcode, $items, $display);
 }
 
@@ -137,3 +139,54 @@
   );
   return $defaults;
 }
+
+/**
+ * Vimeo.com's default thumb settings.
+ *
+ * @see vimeo_link_formatter_field_formatter_settings_form_vimeo_link_formatter_thumbnail()
+ *
+ * @return Array
+ *    Default values keyed by the setting name.
+ */
+function vimeo_link_formatter_default_settings_thumbnail() {
+  $defaults = array(
+    // Cast values to the type that Form API forms return them as.
+    'thumb_size' => (String) 'medium',
+  );
+  return $defaults;
+}
+
+/**
+ * Implementation of vimeo_link_formatter_field_formatter_view_FORMATTER();
+ *
+ * @return Vimeo remote image html
+ */
+function vimeo_link_formatter_field_formatter_view_vimeo_link_formatter_thumbnail($entity_type, $entity, $field, $instance, $langcode, $items, $display) {
+
+  $ret = array();
+
+  foreach ($items as $delta => $item) {
+    // Extract the ID from the URL.
+    preg_match('@http://(www\.)?vimeo\.com/([0-9]+)@', $item['url'], $matches);
+
+    $url = array();
+
+    if ($id = $matches[2]) {
+      $hash = unserialize(file_get_contents("http://vimeo.com/api/v2/video/$id.php"));
+
+      $thumb_size = $display['settings']['thumb_size'] ? $display['settings']['thumb_size'] : 'medium';
+
+      $thumb_url = $hash[0]['thumbnail_'.$thumb_size];
+
+      $img = theme('image', array('path' => $thumb_url, 'alt' => $hash[0]['title']));
+
+      $ret[] = array('#markup' => $img);
+    }
+    else {
+      // The link is not a valid Vimeo.com link.
+      // @todo Handle this better, perhaps with node-form validation or more
+      // formatter settings?
+    }
+  }
+  return $ret;
+}
\ No newline at end of file
Index: vimeo_link_formatter.admin.inc
===================================================================
--- vimeo_link_formatter.admin.inc	(revision 20)
+++ vimeo_link_formatter.admin.inc	(working copy)
@@ -186,3 +186,44 @@
 
   return $form;
 }
+
+/**
+ * Implementation of hook_field_formatter_settings_summary_FORMATTER().
+ *
+ * @return String
+ *    Translated text string summarizing the formatter settings.
+ */
+function vimeo_link_formatter_field_formatter_settings_summary_vimeo_link_formatter_thumbnail($field, $instance, $view_mode) {
+  $display = $instance['display'][$view_mode];
+  $settings = $display['settings'];
+  $summary = t('Use Vimeo video thumb of size "@thumb_size"', array(
+    '@thumb_size'     => $settings['thumb_size'],
+  )); // we use t() for translation and placeholders to guard against attacks
+  return $summary;
+}
+
+/**
+ * Implementation of hook_field_formatter_settings_form_FORMATTER().
+ */
+function vimeo_link_formatter_field_formatter_settings_form_vimeo_link_formatter_thumbnail($field, $instance, $view_mode, $form, &$form_state) {
+   //This gets the view_mode where our settings are stored
+  $display = $instance['display'][$view_mode];
+  //This gets the actual settings
+  $settings = $display['settings'];
+  //Initialize the element variable
+  $element = array();
+  //Add your select box
+  $element['thumb_size'] = array(
+    '#type'           => 'select',                           // Use a select box widget
+    '#title'          => t('Thumbnail Size'),                   // Widget label
+    '#description'    => t('Select what size of Vimeo thumbnail'), // Helper text
+    '#default_value'  => $settings['thumb_size'],              // Get the value if it's already been set
+    '#options'        => array(
+      'small'  => 'Small',
+      'medium' => 'Medium',
+      'large'  => 'Large',
+    ),
+  );
+  
+  return $element;
+}
\ No newline at end of file