How can I sharpen my decal image/not blurry?

I tried using this: http://wiki.roblox.com/index.php/Sharpening_gui_images BUT, I do not understand it at all. Please help me. I want it to be crystal clear like this: http://blog.roblox.com/wp-content/uploads/2012/03/zombie_shootout.png

Um, i have one question, what is this about scripting?

You use ImageRectSize and set it in the resolution order of x, y to your image's resolution.

This is not a scripting related question. You're just modifying properties of a GUI.