access to checkout branding settings and the shop must be on a Plus plan or a Development store plan.
Fields
contentType:
CheckoutBrandingCartLinkContentType -
The content type for the header back to cart link in 1-page checkout. Setting this to image will render the custom image provided using the image field on the header cart_link object. If no image is provided, the default cart icon will be used.
image:
Image -
The image that's used for the header back to cart link in 1-page checkout when the content type is set to image.