rounded corner
I have to ask that you have a previous knowledge of photoshop cs2. Please don't ask for help, unless you feel that there is a problem with the tutorial.

lets get it on!

im going to use this picture to explain.
im sorry if its hard to understand. ill do my best.

okay so open up your picture and get your circle marquee thing, that.
make a circle relatively big, depending on how big you want your edge to be. here's mine
once you've done that, press shift+ctrl+i which will select the inverse of it.like so
then, take a color, or white and paint(or erase) the area, on the background layer. see
make a new raster layer, and put your brushes in it.here
do shift+ctrl+i again and go back to the background layer. see here
then do ctrl c + ctrl v, which will make a new layer, once you've created a new layer, go to layer>layer styles>stroke and set your settings like
this and your drop shadow settings to this
you're going to have to erase the rest of the circle, so just do that. then you're done! not the best, but here's mine