Somewhat of a simple question....

Now, I've read all the memories and I couldn't find any information relating to the question I have. It's sorta simple so I feel kinda silly, but.. here goes..

You know how when you make a transparent background for an icon? Well Sometimes, I used a brush with jagged edges to give the icon a torn and jagged look (sort of like grissom's POTC icon). The only thing is, I don't know how to outline it because it's not a straight line. And I wondered if there was anything easier I could do than zooming in until I select every single little square and paint bucket them black.

Any ideas?


Thanks!