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I am getting 12598 error with a ReviseItem call. What is happening?
There are Restrictions on changing an item's properties with ReviseItem call. The Gallery image is one of them. Once the Gallery images are added to your listing, it's not allowed to remove them in any time. You can add and change the Gallery URL but can not be removed. The error 12598 is just warning that it will not block your ReviseItem request.