Typo3: Skalering af billeder i frontend extension

$image indeholder filnavnet der skal resizes.

$imageConf = $this->conf['image.'];
$imageConf['file'] = "uploads/tx_".$this->extKey."/".$image;
$imageConf['file.']['maxH'] = "25";
//$imageConf['file.']['maxW'] = "25";
$markerArray["###IMAGES###"] .= '<img src="'.$this->cObj->IMG_RESOURCE($imageConf).'" class="thumbnail" />';