Picture link on home page

I am using the Carbon theme and would like to put my own small picture above my introduction on the home page. ( Much like PGTheme). Carbon does not use a special template for the home page, but edits the home page with the 'edit album' sidebar from Gallery2. There is a button for adding the [img] tags, but this seems to require a URL. I cannot figure out the syntax to make a local img appear. Have tried things like -
[img]c:\xxx.jpg[/img]
[img]file:///c:/xxx.jpg[/img]
etc.

Anyone know how to add an image like this ?

TIA !