Nikon D5300 - Manual (Page 46)

26 “Point-and-Shoot” Modes ( i and j)
Viewing Photographs
Pressing K displays a picture in the monitor.
Press 4 or 2 to view additional pictures.
Deleting Unwanted Pictures
Display the photograph you wish to delete.
Press O; a confirmation dialog will be displayed.
Press the O button again to delete the picture.
K button
K button
O button