The links below are to Vietnam War photos to analyze for your assignment. Some are single photographs, some have more than one image on a page, or contain image slideshows.
An American soldier consulting with his South Vietnamese counterparts:
Soldier at a Helicopter landing site:
This site from the New York Times includes a slideshow of images. You can make it full-screen to see the detail on each photo.
A Gallery of Vietnam War photographs, click on individual photo to enlarge:
Soldiers waiting with body of fallen comrade: