Core77

Cardesignnews' "Studio Photos" page is an invaluable resource for auto designers: it's a database of photographs of tons of different cars, all shot from the exact same angle, and presented in a nice, neutral grey on a featureless white background. But while the thumbnails are free, downloading a photo you can actually trace off of requires membership: about US $140 a year for individuals, unless you can sweet-talk your studio or school into getting a group membership.