My sister took a picture of my cat with flash and her eye was yellow. I am worried about it and am wondering if this is normal or not? It only appears in pictures, but if i shine light in her eyes othings shows.
I think you're just catching a reflection from the flash.
It could be worse; there's something called red-eye - the flash reflects off the retina, at the back of the eye through the pupil, and looks red. In fact, looking carefully at the picture you posted, there is some red-eye in the cat's right eye. If your cat had been looking directly at the camera it would have been quite dramatic, very bright, in both eyes.
Photographers can have great difficulties with red-eye; it tends to produce pictures of apparently demonic babies with glowing red eyes. In fact, some cameras have a feature that's intended to prevent it; the flash goes off just before the picture is taken, causing the subject's pupil to contract before it goes off again when the picture is taken.