Hi, I am Lisa Overing and I am a journalist writing a story on Avery Island, Louisiana. The magazine that commissioned my story will give a photo credit to the photographer who provides a nice shot of the salt mines.
I assume that you are not doing this for charity - is a photo credit really ample recompense?
It does annoy me when people (typically journalists and TV production companies) want something for nothing when they are getting paid for it.
If you want to use someone's knowledge, expertese or, as in this case, photos in a commercial context you should be prepared to pay a fair rate.