Delete multiple images at once from a node
I'm a little surprised there's nothing available to empty out a field, but in its absence you can just write your own action for VBO. Contrived (and most likely incomplete) example:

function MYMODULE_action_info() {
  return array(
    'MYMODULE_delete_images' =&gt; array(
      'type' =&gt; 'node',
      'triggers' =&gt; array('any'),
      'label' =&gt; t('Remove all images'),
      'behavior' =&gt; array('changes_property'),
      'configurable' =&gt; FALSE,
      'vbo_configurable' =&gt; FALSE,

    ),
  );
}

function MYMODULE_delete_images_action($entity, $context) {
  // Pick up pre-batch config entered by user.
  $foo = $context['foo'];

  // Remove all field vals. Using 'changes_property' behavior in the
  // info hook will trigger the entity to be saved, so no need
  // to do so manually.
  $entity-&gt;field_FOO[LANGUAGE_NONE] = array();
}

function MYMODULE_delete_images_action_form($context, &amp;$form_state) {
  // Some custom context for the batch op.
  $form['foo'] = array(
    '#type' =&gt; 'textfield',
    '#title' =&gt; t('Some option'),
  );
}

function MYMODULE_delete_images_action_form_validate($form, &amp;$form_state) {
  // Validate the submission.
  if (bar($form_state['values']['foo'])) {
    form_set_error('foo', t('Blah'));
  }
}

function MYMODULE_delete_images_action_form_submit($form, &amp;$form_state) {
  // Ensure submitted values are passed through to the action callback.
  return array(
    'foo' =&gt; $form_state['values']['foo'],
  );
}


Obviously you could extend the pre-batch form to allow for a choice of which field to empty, and even make this generic to all field types with a little effort.