Uh, that was her.
If you've noticed from the previous romero movies, the one theme that he kept consistent in all of them was the carelessness rednecks have when dealing with firearms and other people. In night, that black guy was shot by a redneck at the end. In dawn, rednecks were portrayed to have fun shooting at things and people causing distruction while laughing and joking. In day, rednecks had a total disregard for life and executed the scientists while joking and laughing. In world, rednecks again had a total disregard for life and carried out their duties while joking and laughing causing casualties among the innocents as well as themselves.
Look at that picture at the end again. It's clearly that girl. She wanted to make her way back to Texas so she had to go through hundreds of miles of redneck country. The picture showed her corpse as some kind of trophy. Now, look at it very carefully. Romero likes to put a lot of zombie makeup on his zombies. They are not the modern zombies where they look like you and I. Romero's zombies look like zombies even though they were people walking around just a few minutes ago. The corpse of that girl in that picture looks like a dead person, not a dead zombie.
You really have to remember that Romero likes to put social issues into his zombie movies. Among his favorites seems to be the degradation of society and how rednecks help speeding up the breakdown of society. Shooting innocent people in the chaos and presenting them as trophies seems to be another one of his favorites.
Added by edit.
You think it was a coincidence the picture at the end of the dead girl had the same dress on as the texas girl when she left the mansion?
Edited by Taz, : No reason given.