In the administration options there isn't an option to do that.
Its possible to change the text title only.
I haven't found a way to edit gallery title (php,css), in all files there is "", but I don't understand where is the "GalleryTitle").
Someone can you tell me where is the (php?) file to change this, please?
(Sorry, but I'm not a web developer, I'm CG artist!)
Thanks

Standard themes do not have but so you are either using an old theme or a third party one

Standard themes also have a part like (index.php of default theme):
`

`
You have to change the theme files directly to uses an image as a logo. Please consider to read the theming tutorial.