Legality with photos

Ok so I am kind of new to this.

I am creating a flyer for a car collision center and they want to use photos of
certain cars, Dodges we’ll say. The collision center is affiliated with Dodge
dealerships and they picked up a large dealership recently hence the flyer.

OK, how do I go about getting photos of the vehicles. I can’t legally just rip’em
off sites and PS them (duh) and I was curious how to go about this. Do I choose
some official photos and contact Dodge asking permission and notifying them it
is affiliated with one of their dealerships? Thanks.

and btw the iStockPhotos are laughably garbage.