With a recent steam update you can now easily share screen shots. To take an in-game screenshot press F12 (it should be the defualt key). The screenshot is then saved to the Steam Cloud and you are given the option of the publishing it to your community profile.
Here is my screenshot library as an example:
http://steamcommunity.com/id/tobaccy/sc ... tab=publicOnce you find the screenshot you want click on it then select "full size," this will take you the full picture and then you copy the URL, my example would be
http://cloud.steampowered.com/ugc/56090 ... 952CA61C5/To make this URL viewable in the forum put the tags
before and after the URL (the tag with the / goes on the end).
Here is what the URL looks like the tag: