I tried both your image and mine with no result. I removed the site logo. If I put it back it shows the same as before. If I give you wp-admin credentials wold that help?
The site is mlpas.com
Here is a link to a large woodgrain image:
https://www.dropbox.com/s/fadeuikurs3lot9/large%20woodgrain.png?dl=0
You can crop from the center or how you wish to make it the correct size.
