cyber.core

// Hook in
add_filter( 'woocommerce_paypal_express_checkout_button_img_url' , 'custom_override_woocommerce_paypal_express_checkout_button_img_url' );

// Our hooked in function - $fields is passed via the filter!
function custom_override_woocommerce_paypal_express_checkout_button_img_url( $variablen ) {
     $express_checkout_img_url = '/wp-content/themes/XXXXXX/images/M3_Logo_01.jpg';
     return $express_checkout_img_url;
}

Thank you Takayuki Miyoshi.

Is it possible to do a seperate format on this both?

not the same like General Settings, a own one?

Thank you