Can I change the credit card icons?

The icon used is filterable by adding code to your theme functions.php file. Replace the image URL as follows.

For Braintree:

add_filter( 'woocommerce_braintree_icon', 'custom_woocommerce_braintree_icon' );

function custom_woocommerce_braintree_icon() {
	return 'https://yoursite.com/icon.png';
}

For Paypal Advanced:

add_filter( 'woocommerce_paypal_advanced_icon', 'custom_woocommerce_paypal_advanced_icon' );

function custom_woocommerce_paypal_advanced_icon() {
	return 'https://yoursite.com/icon.png';
}

For PayPal Credit Card (REST):

add_filter( 'woocommerce_paypal_credit_card_rest_icon', 'custom_woocommerce_paypal_credit_card_rest_icon' );

function woocommerce_paypal_credit_card_rest_icon() {
	return 'https://yoursite.com/icon.png';
}


For PayPal Express Checkout:

add_filter( 'woocommerce_paypal_express_icon', 'custom_woocommerce_paypal_express_icon' );

function custom_woocommerce_paypal_express_icon() {
	return 'https://yoursite.com/icon.png';
}

For PayPal Express Checkout:

add_filter( 'woocommerce_paypal_express_icon', 'custom_woocommerce_paypal_express_icon' );

function custom_woocommerce_paypal_express_icon() {
	return 'https://yoursite.com/icon.png';
}

For PayPal Website Payments Pro (DoDirectPayment) :

add_filter( 'woocommerce_paypal_pro_icon', 'custom_woocommerce_paypal_pro_icon' );

function custom_woocommerce_paypal_pro_icon() {
	return 'https://yoursite.com/icon.png';
}

For PayPal Payments Pro 2.0 (PayFlow) :

add_filter( 'woocommerce_paypal_pro_payflow_icon', 'custom_woocommerce_paypal_pro_payflow_icon' );

function custom_woocommerce_paypal_pro_payflow_icon() {
	return 'https://yoursite.com/icon.png';
}