The camera isn't necessary to complete the story in any version, but can be obtained for fun. Putt-Putt can obtain a free camera from Patty Wagon the Gift Cart as she is giving them away free in order to commemorate the opening of the Cartown Zoo.
The camera can be used to take pictures of the many creatures found in the Cartown Zoo. In addition, the camera can be used to take pictures of characters such as Pep and Chuck Wagon.
In the initial release of Putt-Putt Saves the Zoo, Mr. Baldini's picture couldn't be taken because he was inside his grocery store. The 1999 re-release fixed this by having him come out of it after some time passes.