Welcome to Android Central! Can you post an example?
If the image looked normal in the camera viewfinder, then it isn't the lens. It's either the camera hardware or firmware. Do you get the stripes when you take a video as well?
Good question--I'm not sure. Are there any repair shops in your vicinity where you could take the phone in for an estimate? Maybe they're familiar with the problem. Otherwise, they may have to just replace the camera and then see if it helps.