Although im not entirely sure which program you're trying to use, i'll give
it my best shot.
In Word, you can just use the draw tool to draw a border around your
picture. Word 2003 has the draw tool clearly labeled on the toolbar, in word
2007, you will find it in insert:shapes. Depending on your picture, choose
the correct shape and size to fit.
This would pretty much work for all of the other programs as well,
especially if you edited the picture in word, then added it to another
project.
I would recommend opening a new file to do your "photo editing" in.
And of course there's always Photoshop