private function setPrefixes()
{
$pathArray = array($this->optionsProvider->getVarDir());
// The storage dir itself might be null
if ($storageDir = $this->optionsProvider->getStorageDir()) {
$pathArray[] = $storageDir;
}
$this->draftPrefix = implode('/', array_merge($pathArray, array($this->optionsProvider->getDraftImagesDir())));
$this->publishedPrefix = implode('/', array_merge($pathArray, array($this->optionsProvider->getPublishedImagesDir())));
}