[RICK LAKE]

Sandy C The cracks look like they are in the clear. Checking with the dye will tell for sure. There are a couple of reasons this happens
Washing the wheel with the wrong soap
Power washing the tires and wheels
Too much heat coming from the brakes on hot days. I see the black in the corner of the picture. Is that brake dust???
Unless the is a failure of the wheel itself, I wouldn't worry about it. If the car is going to be a show car, Then you buy another set of tires and rims for just this and change them for street driving.
The other thing would be is to have your front brake ducts hooked up in the car and working. This helps cool down the rotors and pads faster and may prevent cracks in the clear.
Last point is cool down the car before putting it away in the garage. 5 minute of easy driving on the motor and the brakes to remove temp from the rotors and calipers. Rick Lake