At blazingsaddle I have a header image which perfectly matches the size available. If I load it via the ‘customised header’ section of the theme editor it displays on first refresh, but then ‘vanishes’ again on subsequent refreshes.
I have compared the code on both sites and can find no obvious differences. To my uneducated brain that suggests my problem is with my WordPress installation, which I have reloaded. No difference!
I have done a search here and cannot find that exact issue so I hope someone can help.