Массив свойств в arResult

echo count($arResult[ITEMS][PROPERTIES][свойство][VALUE]);

<div class="bx_news">

<?foreach($arResult["ITEMS"] as $arItem):?>

<?
   $this->AddEditAction($arItem['ID'], $arItem['EDIT_LINK'], CIBlock::GetArrayByID($arParams["IBLOCK_ID"], "ELEMENT_EDIT"));
   $this->AddDeleteAction($arItem['ID'], $arItem['DELETE_LINK'], CIBlock::GetArrayByID($arParams["IBLOCK_ID"], "ELEMENT_DELETE"), array("CONFIRM" => GetMessage('NEWS_ELEMENT_DELETE_CONFIRM')));

?><div class="oblojka">
   <a id="<?=$this->GetEditAreaId($arItem['ID']);?>">
             <?if($arParams["DISPLAY_PICTURE"]!="N" && is_array($arItem["PREVIEW_PICTURE"])):?>
         <?if(!$arParams["HIDE_LINK_WHEN_NO_DETAIL"] || ($arItem["DETAIL_TEXT"] && $arResult["USER_HAVE_ACCESS"])):?>
            <a href="<?=$arItem["DETAIL_PAGE_URL"]?>"><img
                  class="preview_picture"
                  border="0"
                  src="<?=$arItem["PREVIEW_PICTURE"]["SRC"]?>"
                  width="<?=$arItem["PREVIEW_PICTURE"]["WIDTH"]?>"
                  height="<?=$arItem["PREVIEW_PICTURE"]["HEIGHT"]?>"
                  alt="<?=$arItem["PREVIEW_PICTURE"]["ALT"]?>"
                  title="<?=$arItem["PREVIEW_PICTURE"]["TITLE"]?>"

                  /></a>
         <?else:?>
            <img
               class="preview_picture"
               border="0"
               src="<?=$arItem["PREVIEW_PICTURE"]["SRC"]?>"
               width="<?=$arItem["PREVIEW_PICTURE"]["WIDTH"]?>"
               height="<?=$arItem["PREVIEW_PICTURE"]["HEIGHT"]?>"
               alt="<?=$arItem["PREVIEW_PICTURE"]["ALT"]?>"
               title="<?=$arItem["PREVIEW_PICTURE"]["TITLE"]?>"

               />
         <?endif;?>
      <?endif?>




   </a>
        <?if($arParams["DISPLAY_NAME"]!="N" && $arItem["NAME"]):?>
         <?if(!$arParams["HIDE_LINK_WHEN_NO_DETAIL"] || ($arItem["DETAIL_TEXT"] && $arResult["USER_HAVE_ACCESS"])):?>
            <a class="det" href="<?echo $arItem["DETAIL_PAGE_URL"]?>"><?echo $arItem["NAME"]?></a><br />
         <?else:?>
            <?echo $arItem["NAME"]?><br />
         <?endif;?>
      <?endif;?>

 

/*Нужный нам кусочек
<? foreach($arResult[ITEMS] as $item){ 
   print "Элемент $item[NAME]  <br>"; 
   print "Количество элементов в свойстве: ".sizeof($item["PROPERTIES"]["MORE_PHOTO"]["VALUE"])."<br>------------------<br><br>"; 

} ?>*/

   
</div>

<?endforeach;?>

</div> 

<?foreach($arResult["ITEMS"] as $arItem):?>
   ...
<?endforeach;?>

print "Количество элементов в свойстве: ".sizeof($arItem["PROPERTIES"]["MORE_PHOTO"]["VALUE"]);