Uploaded a custom header image to my server, backed up the default then renamed my custom image (family.jpg) to misty.jpg (theme default). Site header image disappears. Change the default back to a .jpg, and the default shows up.
-rw-r--r-- 1 root root 30102 Feb 8 10:58 misty.bak
-rw-r--r-- 1 root root 42606 May 10 09:45 misty.jpg
Created a test.php file at the document root to test if my jpg might be corrupt, but - yup - it showed up fine.
-rw-r--r-- 1 root root 56 May 10 09:52 test.php
Went the Site Admin route (Presentation > Custom Image Header), and uploaded my family.jpg. Says it uploaded and replaced, but when I view the site, the default is still there. Any ideas at all? I'll put on my grass skirt and wizard's hat if that's what it takes, but I'm stumped.