Don't panic, you DO NOT have to download anything at all to do this!
Everything that I'm about to show you can be done with no additional downloads, unless you just want to download something specifically for this, that is completely up to you.

Everything that you need to do this is already on your PC, if you have Windows that is...

This guide makes use of Microsoft Paint and the free-to-use website Imgur[imgur.com].
If you have a favorite image host that you'd prefer to use, other than Imgur, then please feel free to skip to the next section on how to post that link to the Steam discussions.

Don't panic!!
Just because the key is called 'Print Screen' doesn't mean that it will actually print anything, as in, send it to your printer to be printed. The Print Screen key doesn't work that way.
What it DOES do is function like a screenshot key in most of your games, however it doesn't make the image in any certain location. It saves your current screen image to the mysterious 'clipboard'...
Be careful though!! Every time you press Print Screen, it will 'snap' a new image, overwriting the previous one, unless you saved it already, so make sure to save your image before pressing the Print Screen key again.

Ok, the first thing that we need to do is locate the Print Screen key.
Depending on whether you are on a desktop or laptop, the Print Screen key may be in different locations, or require the use of the Fn (Function) key.

This is the location of the Print Screen key on most standard desktop keyboards:














This is the location of the Print Screen key on most laptop keyboards (also indicates that you should press and hold the Fn (Function) key before pressing the PrntScrn key):











Once you've found your Print Screen key, you can now use it to capture your screen and save it as an image simply by pressing the key, or Fn and the key, in the case of most laptops.

Once you've clicked PrntScrn open Paint.
This little program comes standard on ALL Windows computers and can be found under Start > All Programs > Accessories

With Paint open, you should see a large button in the upper left corner of the program labelled "Paste", click that and your image will open in the program. With your image open in Paint you can now edit it as you see fit, within the limits of MS Paint of course, and then name it and save it to your hard drive.
NOTE: This can be done with ANY image editing software. I promised free earlier, so this is the 'free version'... lol

Ok, now that you have the image saved to your hard drive, let's upload it so that we can link it in the Discussion boards.
Open your browser and navigate to Imgur[imgur.com].
Don't worry, Imgur is free to use and you DO NOT have to create an account, unless you just want to.
When the page loads up, this is what you will see:











At the top of the page is a big green button labelled 'New Post', click it!






When you click the green button, this window will pop up:













Click the 'Browse' button and navigate to your image.
Select it and then press 'Open'. You will then see this:












Click the 'Copy' button and you will be ready to post that link on the Steam Discussion boards.

Ok, you have your screenshot, you've uploaded it to Imgur, or other favorite image host and got the link to that image, now, how do we post it to the Steam Discussions?

Here we go:

Open the Steam interface and navigate to the discussion that you want to post your screenshot to:










Right-click in the empty text box and click 'Paste' or you can simply click in the blank space and press Ctrl+V...

Once the link is pasted into the text box, you can then type whatever message or info that you need to and press the green 'Post Comment' button at the bottom.











There you have it!!
Your link to your screenshot is now posted to a discussion.., mission accomplished!
You can post multiple links to multiple images within the same comment, if need be.

• Go to your profile and select your 'Artwork' or 'Screenshots' link.
  
• Click on the image that you want to link to. An image window will open.
  
• At the top of the image window will be an address. Highlight it, right-click and select 'Copy' or simply press Ctrl+C.
  
• Navigate to the discussion that you wish to post your image in and then right-click in the text box and select 'Paste' or press Ctrl+V.
  
• Add any info or message that you wish and you are done. Click 'Post Comment' and await the reply.

As always, if you have any questions or comments, please feel free to post them below, I will reply as soon as is humanly possible...