Which side of this led is positive and which is negative?

[Stoic Muffins]

Hi, im doing a case mod on a thermaltake overseer case, my goal was to make it a green case instead of a blue case. on the front of the case there is a logo that lights up blue and I wanted to replace it with a green led but don't know which side is negative and which is positive. There is an resistor on one side of the led but Im not sure if its on the negative or positive side.

here are some pictures of the led:
http://imgur.com/a/I8AHs

 

[makkem]

Hi
With most LEDs the flat on the body denotes the cathode (negative).
So on your LED the resistor is connected to the negative.

 

[larkspur]

Here you go: http://www.startingelectronics.com/beginners/components/LED/

The "flattened" side of the LED casing is negative.

Here's another pic: http://en.wikipedia.org/wiki/Light-emitting_diode#mediaviewer/File:LED,_5mm,_green_%28en%29.svg