Patch "expecting array" error when using other modules based imagefield

When using other modules utilizing imagefield such as LinkImageField, you get a nasty error because:

function _epsacrop_get_crop_presets() {
  $actions = _epsacrop_get_crop_actions();
  $presets =  array();
  foreach ($actions as $preset) {
    $presets[$preset['presetname']] = $preset['presetname'];
  }

  return $presets;
}

tries looping through a variable which isn't an array. This is because epsacrop doesn't (currently) detect these other fields and no action presets exist.

The attached patch fixes this by simply checking if $presets is not empty, and is an array before looping.