Why can't I set the image size for my mate9 camera?

Because your mobile phone has turned on the large aperture mode, the large aperture mode is fixed at 12M pixel size, and can be set by turning off the large aperture mode.

2, the method of setting the image size

1) Find the camera on the phone desktop, find the camera and click Open.

2) After clicking Open to enter the mobile phone camera, there is an icon with three vertical dots in the upper right corner of the mobile phone camera, which is the setting icon of the mobile phone. Click the Open Settings icon.

3) Click the Open Camera Settings icon and find the resolution setting item in the icon. I can't find it here. Turn down the volume manually.

4) When you turn to the bottom, there is a setting item of "10M resolution", which is the setting item of resolution. Find the setting item and click Open.

5) After opening this setting item, enter the resolution setting. As you can see here, the current photo pixel is 10M. The larger the value, the higher the pixel of the photo, and the clearer it will be.

6) If you want to take photos with little memory, you can choose the resolutions of 8M, 6M and 5M. If you want to take a clearer picture, choose the resolution of 13M.

7) If I want to choose a clear resolution setting, I will choose the resolution of 13M. After the resolution is selected, go back to the camera and take pictures.