Noise after installing new brake pads?

I just swapped out both my front and back brake pads with the exact same type of pads that were on my bike before, and I'm stumped as to why they're now making noise. I pressed the pistons back as far as I could get them before installing the new pads. I also tried the trick where you loosen the caliper bolts, squeeze the brake handle to center the caliper, and then tighten the bolts to no avail. Is this just a normal amount of noise for new pads? Or is it possible that my rotors are ever so slightly bent? It seems like there's really almost no clearance between the rotors and pads on this new set.

Thank you!