Hi
Yesterday I tried to change all my blogs to ../../header-images.
On 3 of my hosts, 15 blogs, all went well.
On WebHostingPad, when I tried to update the theme header option and save it kept switching to the live blog and telling me 'page not found'. I tried ../wp-content/header-images' but when I saved it froze. At the time I didn't connect it to the change I was making. WebHosting Pad suspended my account for overuse of CPU.
Today I got it re-instated and tried updating another website and the same thing happened.