iPhone randomly takes photos as gray boxes
PROBLEM: I have an iPhone 6 that is updated to the latest OS. For the 3 months, my iPhone has been occasionally taking pictures as gray boxes. The thumbnail shoes up but when I go to review the photo, the photo is fuzzy and it turns into a gray box. The same thing happens when I try opening the same photo on my Macbook. The image attributes reveal that the image is only 16KB in size. I can't attach the corrupted photo file to this thread but here's how it looks like on my Macbook:
WHAT I'VE TRIED:
-I had my iPhone screen repaired at the apple store 2-3 weeks ago and the rep ran diagnostics on my iPhone because I told him it was more laggy recently. He stated that diagnostics was normal. He reset my iPhone just in case.
-The lag disappeared after restoring and updating my iPhone but this photo corruption issue has persisted.
I thought storage was an issue but I still have 1.5 GB of free space left.
HENCE:
What is causing my iPhone photos to become corrupted? It doesn't happen all the time but when it happens, it is highly inconvenient. Thanks!