I agree that you cannot decern much from the picture.
However you may have seen something that is harmless. There is a condition known as spiral wrap which happens when a tire is re-treaded. You may see little bits of chord sticking out all over the tire. This is a totally acceptable condition although it does look sketchy the manufacturer's have ensured us the tire is ok for service.
The chord you would need to see would be the layers of chord which are under the black tread.
You would see white lines like a thin cuorduroy going diagonally across the tire. This may even be hard to spot from far.
Even once this chord is showing most AMM's will allow for the aircrfat to continue to the next available maintence station providing the chord showing does not eceed dpth or wear specs.
Hope this helps.