Cracked, bruised or broken rib? Not sure, but regular chest X-ray can or cannot tell?

Need further work. With this, you'll need further work up. A chest ct scan will tell for sure, but the treatment migh be the same: time. It really depends on your situation and what's injured.
Xray. If you are trying to evaluate a possible fracture, an xray of the ribs is usually the first line of treatment. Usually a chest xray is not the ideal type of xray for this problem.
Regular chest X-ray. ...Might be able to tell, but it doesn't matter. You can't immobilize a rib, and all we recommend is pain relievers (ibuprofen or acetaminophen), rest and ice. Broken, bruised or none of the above, just be patient and it will heal. The only reason to x-ray is if the trauma was severe enough to raise concern for daage to the underlying lung. Otherwise its just unneeded radiation.