Although that's it for the basics, read the rest of this article to see how to customize the name, the URL, or to use a local image.
[Editor's note: Very cool feature; I had no idea you could do this!]
There are three cases when you would need to get your hands into the button bar preferences file (look for it into "~/Library/Preferences/Explorer/english.toolbar.xml" (If you're on a localized OS look, for example, for french.toolbar.xml or whatever language you're using)):
1) If you want to custom the name under a picture:
You need to change the name between the <title></title> anchors
2) If you wanna create or change the link for a logo:
You need to change the URL between the <url></url> anchors
3) When you drag&drop a pict, it won't download it on your hard drive but will point to it on the server. If you prefer to have it local or to use one of your own pictures, you will have to change the URL between the <imageenabled></imageenabled> anchors. If you want to use a local file you would link to it like this (without the quotes):
"file:///Volumes/nameofyourharddrive/whateverfolder/nameofyourfile"
Enjoy!

