The quality settings are the first thing you need to attend to when setting up the D7200, and they come in two parts: quality and size. These have a big impact on what you can do with your images later.
To adjust the quality, hold down this button and turn the rear command dial. The D7200 can save images in the JPEG format, with quality settings of Fine, Normal and Basic. The better the quality, the larger the image file, so this affects memory card capacity. You can also save unprocessed RAW files (Nikon calls them NEF files). These are the largest and offer the highest quality and greatest editing potential later.
To adjust the size, turn the front command dial instead. Here, you can choose between L (large), M (medium) and S (small). This changes the resolution, or megapixels, of saved images. Medium size is half the size of large, and Small is half the size of medium.
Always use the Large size unless you are absolutely certain you only need the smaller resolutions (for web use or presentations, for example). And always use the Fine or RAW quality settings if you can, even if it means buying larger memory cards.