iMac computers come with an iSight digital camera built into the display. The camera lens is visible as a small circle centered at the top of the display, and a light indicates when it is on. The iSight camera works both as a video camera and a still photography camera and can be used in a number of ways with the software that comes as part of OS X.
Take photos with your iMac's built-in camera using Photo Booth. Open Photo Booth from the Applications folder by double-clicking on the icon. A green light will appear next to the camera lens and an image will appear in the Photo Booth menu. Take a basic photo by pressing the red button in the center of the window. Take a photo using special effects by pressing the "Effects" button and choosing from the preset options. Any photos taken in Photo Booth will appear in "User > Pictures > Photo Booth."
Shoot video with your iMac's iSight camera using Photo Booth by selecting the icon that looks like a strip of film from the lower left-hand corner of the Photo Booth window. To start recording, press the red button at the center of the window. To stop recording, press the "Stop" button in the center of the screen. Any videos taken in Photo Booth will appear in "User > Pictures > Photo Booth."
Use your iMac's iSight camera and the iChat application to video conference with others. This requires a MobileMe, AIM, Google Talk or Jabber account. Open iChat by double-clicking on the icon in the Applications folder. Enter your account information in the iChat window and press done. On your buddy list window, you will see a green camera icon. Click on the icon to turn on the video camera. Your image will appear in a window on the screen. When you begin chatting with someone else, they will see the video feed. To turn off the camera, close the window by pressing the red button in the upper left-hand corner.