conditionally add images above product images in the shop loop via a product's custom field

wc-add-image-above-shop-product-images.php

// Requires that you set a custom field on the product with logo_src = image url
function sv_add_logo_above_wc_shop_image() {

	global $product;
	
	// replace the custom field name logo_src with your own
	$logo_src = get_post_meta( $product->id, 'logo_src', true );

	// Add these fields to the shop loop if set
	if ( ! empty( $logo_src ) ) {
		echo '<img src="' . $logo_src . '" class="aligncenter" style="margin-bottom: 20px;" />';
	}
 
}
add_action( 'woocommerce_before_shop_loop_item_title', 'sv_add_logo_above_wc_shop_image', 9 );