i need to change 'image' in this array for my image value
$markup_offer = array(
'@type' => 'Offer',
'price' => $product_price,
'priceValidUntil' => $price_valid_until,
'priceSpecification' => array(
'@type' => 'PriceSpecification',
'price' => $product_price,
'priceCurrency' => $shop_currency,
'valueAddedTaxIncluded' => wc_prices_include_tax() ? 'true' : 'false',
),
'priceCurrency' => $shop_currency,
'itemCondition' => 'https://schema.org/'.$json_condition.'',
'availability' => 'https://schema.org/'.$availability.'',
'sku' => $variable_product->get_sku(),
'image' => wp_get_attachment_url( $product->get_image_id() ),
'description' => $product->get_description(),
'seller' => array(
'@type' => 'Organization',
'name' => $shop_name,
'url' => $shop_url,
),
'url' => $link
);