User blog comment:P進大好きbot/Voting on new site policies/@comment-31040770-20200207142329/@comment-35470197-20200207143908

Thank you.

Proving something in a real world is really difficult unlike mathematics. Instead, we can put a citation or a description of the license. For example, if I upload an image with the description "I am the copyright-holder and upload it under CC-BY-SA licensing", then others can understand the status, although the description is not a proof.