Banner Header change not working

[Tim]

Need advice on changing out my logo header.

I've tried everything I can think of but the header logo remains the original. I've FTP'd the new (winter themed) logo into the images file and saved it under logo2.png. Then I opened the theme css (Streamline Blue) and changed the code from the original logo1.png to logo2.png in the header area. I've even DELETED the original logo1.png file to see what it did because my change was not occuring. After not seeing any change after numerous tries I went back to change the file back to logo1.png as well as within the CSS header. It is pulling the original header logo that does not even exist (I deleted it). How can that be?

It is not a function of Cache as far as I can tell.

Stumped.

This is where I went to make the change in the CSS:
#header #imageheader {
width: 960px;
height: 100%;
text-indent: -10000px;
background: url(images/logo1.png) left top no-repeat;
}