What should I do if the takeaway picture of the US Mission is stolen?

Legal analysis: the other party's behavior infringes the copyright of your photographic works. You can sue the local market supervision administration or the people's court to safeguard your legitimate rights and interests.

Legal basis: Article 1033 of the Civil Code of People's Republic of China (PRC), except as otherwise provided by law or with the express consent of the obligee, no organization or individual may commit the following acts: (1) Interfere with the private life of others by means of telephone, short messages, instant messaging tools, e-mail, leaflets, etc. ; (2) Entering, taking photos or peeping into other people's private spaces such as houses and hotel rooms; (3) Shooting, peeping, eavesdropping or revealing other people's private activities; (4) Shooting or peeping at the private parts of others' bodies; (5) handling other people's private information; (6) Infringe upon the privacy of others in other ways.