There are three different tools on this webpage:
This is the trichromatic image. For trichromatic observer, this should be the most colorful one among the four.
This image simulates the image in the eye of protanopia. That is, the impact of this image to a trichromatic observer is the same as the original image to a protanopic observer
This image simulates the image in the eye of deutanopia. That is, the impact of this image to a trichromatic observer is the same as the original image to a deutanopic observer
This image simulates the image in the eye of tritanopia. That is, the impact of this image to a trichromatic observer is the same as the original image to a tritanopic observer