When I sold my first nonfiction article to a magazine, I didn't realize that I was responsible for finding the supporting artwork as well. When they offered to accept if if I located photographs, I found some available for sale and assumed I had done my job. But when the magazine was preparing for publication, the editor realized they couldn't afford any of the photographs I had found for them, or was able to find in newspapers. I had only a few days to locate a cheap photo before they pulled the article. It wasn't an easy task, either--I had to find a photograph of a boy who had been the unofficial mayor of an unofficial Texan town (i.e. not on the map), whose family had since moved, and who had since died. Furthermore, I'd just had a baby. After hours online and on the phone I managed to connect with somebody who was able to find the family in a phone book, and they were kind enough to send a picture so that my article could be printed. That was the hardest $29 I've ever earned!
Now, when I'm working on a project I research (or take) photos BEFORE I submit the article. It's more professional, and a lot less stressful.