Their response was to repeat:
"In accordance with the IRS tax treaty we were required to withhold 30% from these transactions. Please consult with a local tax professional or the IRS for more information."
Naturally, the few cents deducted from these photos doesn't justify me paying anyone to check it. But the whole idea is bizarre. How could a tax professional tell me anything about this? We have no way of seeing what the difference is between the photos that got withholding deductions and the photos that did not.