The iPhone has a built-in camera that enables you to take pictures and store them on your iPhone. You can tap the photos to zoom in or out of the pictures. You can email the photos to other people, sync the photos with your computer, or upload the photos to a third-party website (sometimes, you may need to download a third-party iPhone app)--of course, you can delete photos as well.
Open the Camera application on your iPhone.
Open the "Camera Roll."
Select the photo you want to delete. Click the trash can at the bottom of the screen.