Originally Posted by FSETH

Looks like the old pads wore the rotor uneven and now that you installed new pads, only a portion of them are hitting the rotor. I imagine that if the whole pad was hitting the rotor, this debris would be scraped off. I would bed the pads in and see what happens after that. It may take a while for the pads to wear in on the rotors. Until then, you may see this.