In order to fulfill the basic functions of our service, the user hereby agrees to allow Xiaomi to collect, process and use personal information which shall include but not be limited to written threads, pictures, comments, replies in the Mi Community, and relevant data types listed in Xiaomi's Private Policy. By selecting "Agree", you agree to Xiaomi's Private Policy and Content Policy .
Are you saving the numbers in Sim or device or Google accounts ? If you try to save the numbers in Sim card you can't add contact pictures . If you save the numbers in Device and Google accounts then you will be able to add contact pictures . See the pop up in the attachment it seems to me that you need to give the Storage permission .