"Does not contain" not returning expected results

Hi Merlin, i am not sure if this is a bug or my understanding of whats expected

I have a view with exposed filter (cck field) and all options work except "Does not contain" , which returns unexpected results,

I have assumed that I can use this option to search for a string which is part of "myfield" and return all results not containing the string

I have a "myfield" containing image names for example "myimage1.jpg"

if i filter "myimage1.jpg" i return results as expected - anything not containing "myimage1.jpg"

if i filter "mage1.jpg" i return results as expected - anything not containing "mage1.jpg"

if i filter ".jpg" or "jpg" i get no results returned

$view = new view;
$view->name = 'admin_encylopedia_places';
$view->description = 'Admin only view of Places encyclopedia entries against Map';
$view->tag = '';
$view->view_php = '';
$view->base_table = 'node';
$view->is_cacheable = FALSE;
$view->api_version = 2;
$view->disabled = FALSE; /* Edit this to true to make a default view disabled initially */
$handler = $view->new_display('default', 'Defaults', 'default');
$handler->override_option('fields', array(
  'title' => array(
    'label' => 'Title',
    'link_to_node' => 1,
    'exclude' => 0,
    'id' => 'title',
    'table' => 'node',
    'field' => 'title',
    'relationship' => 'none',
  ),
  'field_world_value' => array(
    'id' => 'field_world_value',
    'table' => 'node_data_field_world',
    'field' => 'field_world_value',
  ),
  'field_nation_value' => array(
    'id' => 'field_nation_value',
    'table' => 'node_data_field_nation',
    'field' => 'field_nation_value',
  ),
  'field_find_on_map_value' => array(
    'id' => 'field_find_on_map_value',
    'table' => 'node_data_field_find_on_map',
    'field' => 'field_find_on_map_value',
  ),
  'field_tag_value_1' => array(
    'label' => 'Tag',
    'link_to_node' => 0,
    'label_type' => 'widget',
    'format' => 'default',
    'multiple' => array(
      'group' => 1,
      'multiple_number' => '',
      'multiple_from' => '',
      'multiple_reversed' => 0,
    ),
    'exclude' => 0,
    'id' => 'field_tag_value_1',
    'table' => 'node_data_field_tag',
    'field' => 'field_tag_value',
    'relationship' => 'none',
  ),
));
$handler->override_option('sorts', array(
  'title' => array(
    'id' => 'title',
    'table' => 'node',
    'field' => 'title',
  ),
));
$handler->override_option('filters', array(
  'type' => array(
    'operator' => 'in',
    'value' => array(
      'encyclopedia' => 'encyclopedia',
    ),
    'group' => '0',
    'exposed' => FALSE,
    'expose' => array(
      'operator' => FALSE,
      'label' => '',
    ),
    'id' => 'type',
    'table' => 'node',
    'field' => 'type',
    'relationship' => 'none',
  ),
  'field_group_value' => array(
    'operator' => 'or',
    'value' => array(
      '504' => '504',
    ),
    'group' => '0',
    'exposed' => FALSE,
    'expose' => array(
      'operator' => FALSE,
      'label' => '',
    ),
    'id' => 'field_group_value',
    'table' => 'node_data_field_group',
    'field' => 'field_group_value',
    'relationship' => 'none',
    'reduce_duplicates' => 0,
  ),
  'field_world_value' => array(
    'operator' => 'or',
    'value' => array(
      '593' => '593',
      '797' => '797',
      '594' => '594',
      '798' => '798',
      '679' => '679',
      '801' => '801',
    ),
    'group' => '0',
    'exposed' => TRUE,
    'expose' => array(
      'use_operator' => 0,
      'operator' => 'field_world_value_op',
      'identifier' => 'field_world_value',
      'label' => 'Content: World - (field_world)',
      'optional' => 0,
      'single' => 0,
      'remember' => 0,
      'reduce' => 0,
    ),
    'id' => 'field_world_value',
    'table' => 'node_data_field_world',
    'field' => 'field_world_value',
    'relationship' => 'none',
    'reduce_duplicates' => 0,
    'override' => array(
      'button' => 'Override',
    ),
  ),
  'field_find_on_map_value' => array(
    'operator' => '=',
    'value' => '',
    'group' => '0',
    'exposed' => TRUE,
    'expose' => array(
      'use_operator' => 1,
      'operator' => 'field_find_on_map_value_op',
      'identifier' => 'field_find_on_map_value',
      'label' => 'Content: Find on Map - (field_find_on_map)',
      'optional' => 1,
      'remember' => 1,
    ),
    'case' => 0,
    'id' => 'field_find_on_map_value',
    'table' => 'node_data_field_find_on_map',
    'field' => 'field_find_on_map_value',
    'relationship' => 'none',
  ),
));
$handler->override_option('access', array(
  'type' => 'role',
  'role' => array(
    '3' => '3',
    '5' => '5',
  ),
  'perm' => '',
));
$handler->override_option('title', 'Admin Encyclopedia Places');
$handler->override_option('header_format', '3');
$handler->override_option('footer_format', '3');
$handler->override_option('empty_format', '3');
$handler->override_option('items_per_page', 200);
$handler->override_option('use_pager', '1');
$handler->override_option('distinct', 1);
$handler->override_option('style_plugin', 'table');
$handler->override_option('style_options', array(
  'columns' => array(),
  'default' => '',
  'info' => array(),
  'override' => FALSE,
  'order' => 'asc',
));
$handler = $view->new_display('page', 'Page', 'page_1');
$handler->override_option('path', 'admin_encyc_places');
$handler->override_option('menu', array(
  'type' => 'none',
  'title' => '',
  'weight' => 0,
  'name' => 'navigation',
));
$handler->override_option('tab_options', array(
  'type' => 'none',
  'title' => '',
  'weight' => 0,
));

Query SELECT DISTINCT(node.nid) AS nid,
   node.title AS node_title,
   node_data_field_world.field_world_value AS node_data_field_world_field_world_value,
   node_data_field_world.nid AS node_data_field_world_nid,
   node.type AS node_type,
   node_data_field_find_on_map.field_nation_value AS node_data_field_find_on_map_field_nation_value,
   node_data_field_find_on_map.nid AS node_data_field_find_on_map_nid,
   node_data_field_find_on_map.field_find_on_map_value AS node_data_field_find_on_map_field_find_on_map_value,
   node.vid AS node_vid
 FROM node node 
 INNER JOIN content_field_group node_data_field_group ON node.vid = node_data_field_group.vid
 INNER JOIN content_type_encyclopedia node_data_field_world ON node.vid = node_data_field_world.vid
 LEFT JOIN content_type_encyclopedia node_data_field_find_on_map ON node.vid = node_data_field_find_on_map.vid
 WHERE (node.type in ('encyclopedia')) AND (node_data_field_group.field_group_value = '504') AND (node_data_field_world.field_world_value IN ('593', '797', '594', '798', '679', '801')) AND ((node_data_field_find_on_map.field_find_on_map_value) NOT LIKE ('%.jpg%'))
   ORDER BY node_title ASC