I’m confused by your request. You are wanting help with your site logo or with the Super Cache plugin? If you are looking for help with your logo, please leave a link to your site. Editing your logo will depend on your theme, but usually you create the logo image the way you want it and then upload it to the theme. Sometimes you need to adjust the height of the logo area in your CSS.
Also, if you are making changes to your site while you have the Super Cache plugin activated, you will probably not see those changes. You need to deactivate it while you are editing your site and then reactivate it when you are done.
