SSL-Error because Slider

Hi! I bought an SSL-certificat from my Provider. It works very well, but not at the the (start)-side where the Catch Box Pro-Slider ist located. It seems because that html-code in the theme http://www.sz-law.de/wp-content/themes/catch-box-pro/images/previous.png The Next-and Previous-Button at the slider is not linked with an https://-Link. My Provider say thats why it doesn't work. The General Settings at WP contains the side: https://www.sz-law.de Can you help me please? Thx Alexander