Why do people have red eyes in flash photographs?

the flash lights to the lens back by hitting retina of the eye so the eyes look in red color, when we take a photo graph.

Red eye occurs when using a photographic flash very close to the camera lens (as with most compact cameras), in ambient low light. Red-eye effect appears in the eyes of humans and animals that have no tapetum lucidum (a layer of tissue in the eye), hence no eyeshine,[citation needed] and rarely in animals that have a tapetum lucidum. The red-eye effect is a photographic effect, not seen in nature.

your right why there is red eye on it, it become question also to me, we cannot say because of the flash because we are using also flash in dalight sometimes.

that would be from our eyes dilating and reflecting the light from the flash. Sort of how a cat's eyes will glow at night. Some cameras have the red eye feature which gives a series of short flashes just prior to taking the picture, in that way the eyes have already contracted from the bright light and there will not be that red reflective effect. so glad picture programs now make it easy to remove red eye.... red eye can sure ruin an otherwise beautiful photograph.

I guess it has to do with the lighting. The red eyes often manifest distortion because either the lights are reflected by the eyes thus red eyes occur. :D

Lol this is so funny to me. I almost always have red eyes in photos. It usually happens to people who have light eyes ( green or blue). I have blue-grey eyes so I quite frequently end up with red eyes in pictures. I'm not really sure about the whole light theory about this. I guess if you're around a lot of people with brown eyes you wouldn't see this very much though.

Since I do not believe in the devil, I shall have to go with the light theory. Here it is in easily understandable form: http://science.howstuffworks.com/question51.htm Enjoy! Yes, another excellent topic here, thank you!