So presumably you are using a PictureBox?
Load your two images in teh constructor, and store them in class level variables:
private static Image cameraOff;
private static Image cameraOn;
...
cameraOff = Image.FromFile(@"D:\Temp\Images\CameraOff.png");
cameraOn = Image.FromFile(@"D:\Temp\Images\CameraOn.png");
pictureBoxWithCamera.Image = cameraOff;
...
When you want to set the picture to the On image:
pictureBoxWithCamera.Image = cameraOn;
When you want it back to Offf:
pictureBoxWithCamera.Image = cameraOff;