can't change home page logo picture

I'm an additional admin person (just added) and can't create a servimg account or use my photobucket account or figure any way that allows me to change the picture on my home page. The original admin person has a gallery in the admin page setup area, but I need to add pictures to it, or create my own gallery to use. Nothing I've tried works. I even went to the servimg web site and tried to create an account. I've read some of the forums and the servimg tutorial but the sentence structure looks like a translation from Japanese to English maybe, and doesn't make sense.