SSL issue with a form

I have two forma on this page. The large form on this page (left) is making the form insecure for some reason. Can you help me figure out how to resolve the issue. When I remove the form the page becomes secure but when I put it back it is not.

Thank you for contacting us.

The reason why your form is insecure is due to the images on the purchase order payment integration. Since, the images are in http protocol.

I cloned your form to my side and change them to https protocol and the form becomes secure again. So, please change on all the product images protocol on your payment setting.

If you need any further assistance by our side, please feel free to contact us. We would be pleased to help you.