How to launch draw9patch and is it absolutely necessary to rescale pictures?

Question

I read on another forum that to launch draw9pad from your console, you have to do java -jar draw9patch.jar from the command prompt once youre in sdk. I did that but i still cannot launch the file. Is this tool absolutely necessary for your pictures to scale on different screens? I know that eclipse has these drawable folders that scale your pictures to different dpis or is that not what they do? Console output: http://imgur.com/YdGLHXr

File skd/tools :http://imgur.com/vOU647L

Answer 1

To answer the first question for a Mac OS or Linux user, simply type sh draw9patch to launch the editor. CommonsWare already answered the second question.