Conditionally run function based on custom meta value?

Instead of conditionally adding an add_action() call, you can just add it and run the function it hooks to—its callback—conditionally instead.

For example:

add_action( 'woocommerce_product_additional_information', 'wpse407073_callback' );
add_action( 'woocommerce_after_shop_loop_item', 'wpse407073_callback' );

function wpse407073_callback( $product = null ) {
    if ( empty( $product ) ) {
        global $post;
        $product = $post;
    }
    if ( 'X' === get_post_meta( $product->ID, 'my-custom-meta-field', true ) ) {
        echo '<img src="image.jpg" alt="Image Name">';
    }
}

A few points:

• Having looked quickly at WooCommerce’s code, woocommerce_after_shop_loop_item doesn’t pass anything to the callback, and woocommerce_product_additional_information passed 1 parameter, $product, which I’m assuming is a custom post. That’s why I added a check for an empty $product in the callback.
• This code hasn’t been tested, and is meant as a possible starting point, not a finished product.
• If you have questions about WooCommerce’s hooks, you should check with WooCommerce’s documentation and/or their support team.