Error "zom.product.group.imagenotattached"

Error "zom.product.group.imagenotattached"

I am executing a requset api for posturl method in which the image has to be updated in the zoho inventory item details.
While executing the api, I get the error mesage as 

{"code":33003,"message":"zom.product.group.imagenotattached"}.


What it denotes, is there any other options for sending images to the zoho inventory??