legal ground
Article 27 of the Patent Law of People's Republic of China (PRC)
To apply for a patent for design, a request, a picture or photograph of the design, a brief description of the design and other documents shall be submitted.
The relevant pictures or photographs submitted by the applicant shall clearly indicate the design of the product for which patent protection is required.
Article 33
The applicant may modify his patent application documents, but the modification of the application documents for patents for inventions and utility models shall not exceed the scope recorded in the original specifications and claims, and the modification of the application documents for patents for designs shall not exceed the scope shown in the original pictures or photographs.