My Nikon D40 has a rectangle with yellow 'waves' in it on the digital screen. This rectangle partly covers my photos in the display window. It is very annoying. Not sure if I have pushed a button to cause it to show up or not... I have no idea where it appeared from. I have tried pushing buttons to get rid of it but to no avail. Help please. I am a raw beginner.
The only thing that comes to my mind would be the histogram:
Hit the 'play button' so you see the single image (with histogram). Then hit the 'up' or 'down' buttons on the wheel on the right side of the back of the camera.
That cycles through two information screens, histogram and regular display.