You will see the error below if Trade Me detects the same image being used on two different listings.
How to Fix
Change the images on your products in your eCommerce store so that each listing uses a unique image or image URL.
After making the changes, perform an import in Omnivore so the updated images can be imported and sent to Trade Me.
Alternative Option
You can also exclude the image(s) in Omnivore, preventing them from being sent to Trade Me.
For instructions on how to exclude or block images in Omnivore, please follow this FAQ.