How to Protect Photos on Your Nikon D7100
You can safeguard pictures from accidental erasure by giving them protected status on your Nikon D7100's memory card. After you take this step, the camera doesn’t allow you to erase a picture by using the Delete button or the Delete option on the Playback menu.
Formatting your memory card, however, does erase even protected pictures. In addition, when you protect a picture, it shows up as a read-only file when you transfer it to your computer. Files that have that read-only status can’t be altered until you unlock them in your photo software.
In Nikon ViewNX 2, the software that ships with your camera, you can do this by clicking the image thumbnail and then choosing File→Protect Files→Unprotect.
Protecting a picture is easy:
Display or select the picture you want to protect.
In single-image view, just display the photo.
In 4/9/72 thumbnail mode, use the Multi Selector as needed to place the yellow highlight box over the photo.
In Calendar view, highlight the image in the strip of thumbnails that appears on the right side of the screen. (Press the ISO button to jump between the calendar dates and the thumbnails.)
Press the WB button.
See the key symbol on the button? That’s your reminder that you use the button to lock a picture. The same symbol appears on protected photos during playback.
To remove protection, display or select the image and then press the WB button again.