Hi Yongmin,
Is there any doubt that the images are submitted by their photographer? If it is clear that the image is submitted to Wikimedia Commons by its author, it is usually not considered a problem.
Sometimes an earlier submission to another website is an indication that the submission to WLM is not by its original author - this is why sometimes this becomes a problem (people doubt the submission is truthful). If you have such doubt, just send a quick email to the original account/website where the image was first published and ask them to confirm it's the same person.
Best,
Lodewijk