Joomla eXplorer is a File- and FTP – Manager. It allows you to edit files, delete, copy, rename, archive and unpack files/directories directly on your server. You can – Browse Directories & Files – Edit, Copy, Move and Delete files – Search, Upload and Downloading files – Create new files and directories – Change file permissions (chmod) and much more This script is based on QuiXplorer 2.3.1

Download it Here

This a the tool that you will use to update and change the header image in your template.

also you can browse all of your files in joomla. This has Ftp built into it.