Override all themes?

Hi all,

I wanted to make it so that when I search for images a thumbnail of the image appears in the search engine next to the decription of the image.

I'm using the default search module but I went through the process of overriding the theme I am using in order to make "search" do what I what it to. It all works but only for the theme that I "overrided."

I'm just wondering if there is an easy way to override ALL of my themes or if I will have to paste the template.php into all my themes' folders.

Any suggestions would be nice.

Thanks for reading.