Script-Fu -> Copyright Text
This is an adjustable script,
it adds copyright information to the photo.
Script-FU > Photo > Copyright Text
BTW: The COPYRIGHT symbol is included with my name in the defaults for the script.
Just backspace out my name and put in what you neecd to...
And if you need to use a copyright symbol anytime while in the GIMP,
(an underlined "u" will appear)
Then type a9 and press the ENTER key.
That little trick works in most operating systems (tested on Windows 8.1 and Absolute Linux just today :-)type a9 and press enter