Eyes appearing Red after taking a picture is a sign of health problems. (Red Eye Effect)

This is caused by light reflecting off the eye's retina, making the eyes appear red. However, sometimes only one eye appears red, and the other eye appears white. This is often an indicator for many dangerous health problems including melanoma and retinoblastoma - very dangerous cancers.

You can detect infrared light (IR) using your smartphone camera

^{Your remote emits infrared light (IR) that your eyes cannot detect, but most digital cameras can see it quite easily. Just aim the camera at the top of the remote, and push a button on the remote while looking into the camera. You'll see the infrared light as shown in the picture.}