Turn it to 30.
Find the photo in the iPhone, click the muscle photo you want to modify, and click Edit in the upper right corner to adjust the contrast. It is recommended to adjust the structure to 60 for maximum muscle display.
After the camera is turned on, the volume plus and minus buttons can also be used as the shutter button, in addition to the shutter button (shooting button) of the white circle. It is no longer necessary to click the white circle with the other hand when taking a selfie