How to view the full picture on my Nikon D300?

I just got a Nikon D300. My mom was looking through the pictures and she said she pressed some button on the camera, and now whenever I try to view the pictures on the camera screen there's only a tiny thumbnail version on the top left corner with the rest of the screen black with white writing. I've been pressing buttons trying to get back to viewing the whole picture on the screen but I can't figure it out. Does anyone know how I can go back to the viewing the whole picture on the camera screen?

The magnifiying glass on the left of the screen or the down arrow on the directional pad.

Might wanna read the manual, the D300 is a highly complicated piece of camera.

Press the disp bhutton. It's disp[laying info about the image.

The large round button to the right of the display. It is called the "multifunction" button and it is not labeled. Press either the 12:00 or 6:00 position until you get the view that you want. The options include the one you are seeing, one where the highlights flash on and off if they are overexposed, and the one you want. That's it.