You can set your own home logo and use a Gravatar avatar.
Home logo
You can set your own home logo in Administration > General Settings > General > Look & Feel.
Simply provide an image URL and width. This logo will be used in the menu bar.
Gravatar
Gravatar support is enabled by default, using gravatar.com. You can configure a different server or disable the feature altogether. When enabled, gravatars show up next to most uses of the user name.
