Why doesn't my custom label appear at checkout?

We sell customised labels, issue is the customised label doesn’t appear in the check out and people are abandoning the check out as they don’t think it’s their design. The Customised Image is correct in the cart but not carried through to the check out. We are only starting out and can’t justify PLUS to be able to make these changes in our cart. Is there a Cart Pop Up I can use to notify purchasers that the image displayed in the checkout is generic?