This code will add the merchant logo (if the logo exists) to the WooCommerce single product page. [datafeedr]

add-merchant-logo-to-product-details-page.php

<?php

/**
 * Add merchant logo (if it exists) to product details page.
 *
 * This displays the merchant's logo before the [buy now] button on
 * single product detail pages.
 *
 * @global WC_Product $product
 */
function mycode_add_merchant_logo_to_single_product_page() {

	global $product;

	if ( ! dfrpswc_is_dfrpswc_product( $product->get_id() ) ) {
		return;
	}

	$postmeta = get_post_meta( $product->get_id(), '_dfrps_product', true );

	$merchant_id   = absint( $postmeta['merchant_id'] );
	$merchant_name = esc_html( $postmeta['merchant'] );
	$img_alt       = esc_attr( $postmeta['merchant'] );

	$url = 'https://images.datafeedr.com/m/' . $merchant_id . '.jpg';

	echo '<style type="text/css">.dfr_missing_logo span{display:inline;}.dfr_missing_logo img{display:none;}</style>';
	echo "<img onerror='this.parentNode.className += \" dfr_missing_logo\"' src='$url' alt='$img_alt' title='$img_alt'><span style='display:none;'>$merchant_name</span>";
}

add_action( 'woocommerce_external_add_to_cart', 'mycode_add_merchant_logo_to_single_product_page' );