Grey's Anatomy is a famous book on human organs available at any library. Here on this site a double click on any word will take you to more in depth information including pictures.
Most any library on Earth that has an Anatomy section will include diagrams of sexual/reproductive organs of humans, including the penis. If you're looking for something more prurient, there are...
It may be best to do an Image search on your favorite search engine to find such a picture there. Just type in "camel penis" and you'll probably find what you're looking for there.