Nikon Z9 Mirrorless Camera - Manual (Page 105)

105 Image Recording Options (Image Area, Quality, and Size)
Adjusting Image Quality
Choose the image quality option used when photographs are recorded.
❚❚
Choosing an Image Quality Option
Hold the T button and rotate the main command dial.
A The Photo Shooting Menu [Image Quality] Option
Image quality can also be adjusted using the [ Image quality ] item in the
photo shooting menu.