CFileWater::$watermark['position'] = 'br';
CFileWater::$watermark['file'] = CFileWater::$watermark['file_small'];
$arOfferPicture = CFileWater::ResizeImageGet($iOfferPicture,   array('width' => 250, 'height' => 250),   BX_RESIZE_IMAGE_PROPORTIONAL_ALT);

$watermark = array(
   array(
               'position' => 'br',
               'type' => 'file',
               'size' => 'real',
               'alpha_level' => 100,
               'file' => '/upload/watermark.png',
   )
); 
$arOfferPicture = CFile::ResizeImageGet($iOfferPicture,   array('width' => 250, 'height' => 250),   BX_RESIZE_IMAGE_PROPORTIONAL_ALT, false, $watermark);

if(is_array($arFilters))
 {
    foreach($arFilters as $arFilter)
    $bNeedCreatePicture |= CFile::ApplyImageFilter($picture, $arFilter, $bHasAlpha);
}
if(is_array($arWaterMark))
{
   $arWaterMark["name"] = "watermark";
   $bNeedCreatePicture |= CFile::ApplyImageFilter($picture, $arWaterMark, $bHasAlpha);
}