How to add screenshots?

I've seen these very handy screenshots of JASS code and triggers in GUI in the posts of many people. I was wondering how do you attach those to you're posts?

use [jass]what ever jass code [./JASS] and [trigger]gui trigger stuff [./TRIGGER] and its not actually screenshots, to post screenshots (dont do it for Jass or GUI though) press Printscreen on your key board then open paint and press ctrl+v and vwala theres your screenshot

yes, they aren't actually screenshoots IE:
Untagged JASS:
function OMG takes nothing returns nothing
call DisplayTextToForce(GetPlayersAll(), "This is a test")
endfunction
Tagged JASS with the "[jass]":
Untagged GUI:
My Trigger
Events
A Unit Dies
Conditions
(Dying Unit) is equal to Footman
Actions
Game - Display To All Playeres the Text: He Died
Tagged GUI with the "[trigger]"

Select the trigger content in the post above with mouse, you will se it is not an picture ;)