Adding an Image inside PHP code?

[limelites]

I still haven't managed to figure this out, it's really difficult with my limited knowledge of PHP.

I see that the Paypal module puts a Paypal image on the checkout page using this code:

  define('MODULE_PAYMENT_PAYPALWPP_MARK_BUTTON_IMG', 'https://www.paypal.com/en_US/i/logo/PayPal_mark_37x23.gif');
  define('MODULE_PAYMENT_PAYPALWPP_MARK_BUTTON_ALT', 'Checkout with PayPal');
  define('MODULE_PAYMENT_PAYPAL_ACCEPTANCE_MARK_TEXT', 'Save time. Check out securely. <br />Pay without sharing your financial information.');

  define('MODULE_PAYMENT_PAYPAL_TEXT_CATALOG_LOGO', '<img src="' . MODULE_PAYMENT_PAYPALWPP_MARK_BUTTON_IMG . '" alt="' . MODULE_PAYMENT_PAYPALWPP_MARK_BUTTON_ALT . '" title="' . MODULE_PAYMENT_PAYPALWPP_MARK_BUTTON_ALT . '" /> &nbsp;' .  '<span class="smallText">' . MODULE_PAYMENT_PAYPAL_ACCEPTANCE_MARK_TEXT . '</span>'); 

However, when I try to alter this and add it to the nochex php file it doens't work.

Can anyone tell me how I could modify this code to generate credit card images next to the nochex radio button in a similar way that the Paypal image appears next to the Paypal redio button?