How to delete a protected image on a Nikon D3100?

I have a couple pictures I took on my D3100 that some became "protected pictures," I don't know how they got that way, and I'd like to delete them.

Format the card in your camera.

The first thing you need to do is STOP using the delete button on your camera. It almost guarantees that the memory card will eventually become corrupted,

This is what you should be doing.

* at the end of each shooting day, copy All the images to your computer to a new file folder you have named for the subject and date. This way you will be able to find them later
* once the images are safely on your computer, format the card using the format feature on the camera.

Do this routinely and you will never have a corrupted memory card.

Look on page 108 of your user manual to see what you did to "protect" those files

Scroll back and find the photos in question on your camera's lcd screen. When you see them, press the button on the back of your D3100 that has a icon of a key. You'll find it as the second-from-the bottom button on the left side. That button locks or unlocks photos so they don't get accidently deleted.

Don't worry, we've all accidentally pressed different buttons on our camera by mistake or even had them pressed when the camera's put in our camera bags.

Afterwards, follow the sage advice of the others posted here and always format your memory card in the camera between uses. Don't format it in the computer and don't use your memory card for longterm storage.

The Key worked!