This is a photograph from the collection of Dedria Ashworth. I have her permission to use it.
One of the students in my WordPress class was asking about the changing the header. The instructor gave some simple instructions to prepare the photo for the header. I took those instructions and was able to choose a section of this photo to make it fit in the header.
1. In Appearance>Theme>Header : Check the size of the header.
2. Find a photo that is in landscape not portrait. (Unless your header has a picture in landscape.)
3. Then open the Photo in Photoshop.
4. Use the Change Canvas setting, and put in the dimensions from the head.
5. Experiment until you have the section you want to use.
6. Save the photo as a .jpg (this was originally a .tiff), I saved to my desktop.
7. Back to Appearance>Theme>Header
8. Browse for the photo Upload, select the new photo, SAVE.
These instructions are for me, if I ever want to change the header again.