I will be travelling to the US for a vacation. I would like to rent a car for driving there but I have recently lost the original card license that I own. I have a scanned copy of my licence though. Will I be able to drive in the US legally with a photocopy of my licence and an IDP ? Will the police in California accept it ?
No and no. :(
But your first problem is you will be unable to rent a car without a valid Driver License. There is practically 0% change a reputable agency will accept a photo copy of anything.