diff --git image.install image.install
index 8700f25..1e24d15 100644
--- image.install
+++ image.install
@@ -317,20 +317,20 @@ function image_update_6100() {
     'default' => 0,
   ));
 
-  /**
-   * We remove and re-add primary keys and indexes because the column types
-   * are changed.
-   * Sometimes however these don't exist in the first place (@see
-   * <http://drupal.org/node/562810>; the @ takes care of suppressing the
-   * error message this causes.
-   */
+  // We remove and re-add primary keys and indexes because the column types
+  // are changed. Sometimes however these don't exist in the first place.
+  // @see http://drupal.org/node/562810
+  // Try to suppress errors during removal.
   @db_drop_primary_key($ret, 'image');
   db_add_primary_key($ret, 'image', array('nid', 'image_size'));
   @db_drop_index($ret, 'image', 'image_fid');
   db_add_index($ret, 'image', 'fid', array('fid'));
 
   // Notify the user that they may get harmless fail messages here.
-  $ret[] = array('success' => TRUE, 'query' => t('If you see a message of the form "Failed: ALTER TABLE {image} DROP PRIMARY KEY" or "DROP INDEX image_fid" here it is harmless.'));
+  $ret[] = array(
+    'success' => TRUE,
+    'query' => t('You can safely ignore the error message "Failed: ALTER TABLE {image} DROP PRIMARY KEY" or "DROP INDEX image_fid".'),
+  );
   return $ret;
 }
 
@@ -382,8 +382,13 @@ function image_update_6103() {
  */
 function image_update_6104() {
   $ret = array();
-  $query = "ALTER TABLE {image} ALTER COLUMN image_size SET DEFAULT ''";
-  $ret[] = update_sql($query);
+  db_change_field($ret, 'image', 'image_size', 'image_size', array(
+    'description' => 'Primary Key: The {files}.filename of the image file. For image module this indicates the file size.',
+    'type' => 'varchar',
+    'length' => 32,
+    'not null' => TRUE,
+    'default' => '',
+  ));
   return $ret;
 }