VarIzo

"select" => [
            "*",
            "SECTION_NAME" => "SECTION.NAME",
            "PRICE" => "PRICE_LIST.PRICE",
            "QUANTITY" => "PRODUCT.QUANTITY",
        ],
'runtime' => [
            'PRICE_LIST' => [
                'data_type' => \Bitrix\Catalog\PriceTable::class,
                'reference' => [
                    '=this.ID' => 'ref.PRODUCT_ID',
                ],
                'join_type' => 'left'
            ],
            'PRODUCT' => [
                'data_type' => \Bitrix\Catalog\ProductTable::class,
                'reference' => [
                    '=this.ID' => 'ref.ID',
                ],
                'join_type' => 'left'
            ],
            'SECTION' => [
                'data_type' => \Bitrix\Iblock\SectionTable::class,
                'reference' => [
                    '=this.IBLOCK_SECTION_ID' => 'ref.ID',
                ],
                'join_type' => 'left'
            ],
        ],

$img = CFile::GetPath($product['PREVIEW_PICTURE']);