Photos look like night vision images

Photos taken with my iPhone 5S suddenly started coming out looking like an image seen through night vision goggles — see attached image. When it started happening the phone had iOS 10.something.

So I reluctantly upgraded to iOS 11 (concerned that it would slow my phone down too much) which had just came out when the problem happened. The upgrade did indeed slow my phone down but it also fixed my image troubles... briefly. It worked correctly for three photos, then the fourth one started coming out green again. So now I had very slow phone AND green photos.

So I downgraded back to iOS 10 and the same thing happened. The first few photos were fine, then it was back to the exact same green photo issue.

Because the OS change would temporarily help I was assuming it was a software issue. But the fact that it keeps coming back, now makes me think that there is actually a hardware problem with the camera.

Thoughts?