Is what I did considered a sin, and what is the ruling on arguing about religious matters, after I forbade my friend from asking too many questions about the prohibition of photographic images?

We have previously discussed the scholarly disagreement regarding photographic imaging, and the more cautious approach is to avoid it when there is no need for it. It would be good to explain to the questioner that the issue is subject to scholarly disagreement, and that there is latitude in this disagreement. People should not be forced to adhere to a single opinion. He should follow whoever he trusts in their knowledge and piety, and he should not condemn those who differ as sinful. Opposing the rulings of Sharia with mere personal opinion is forbidden.