Solution: 

To post a picture in these forums this is what you can do.
You will need the picture hosted somewhere. You can host is on your profile or use various hosting websites such as photobucket.com, flickr.com or the one we recomend, tinypic.com

If its not uploaded on your profile this is what you can do:

1. go to www.tinypic.com
2. Click browse
3. Locate and select picture on your computer
4. Press upload now
5. Now a screen will come up with a bunch of links:
6. Highlight: [img]yourpic.jpg[img]
7. Press copy (or control c or apple c for macs)
8. Go back to the forum post
9. Right click on message body and press paste (or control v)
10. Finish editing post and press submit

If your image is uploaded on your profile this is what you can do: (This method works for almost any picture on the web)

1. Go to your profile.
2. Go to your personal gallery, (The pictures tab by your friends)
3. Click on the picture you would like to display in the forum
4. Once opened right click on the picture
5. On that detaled information page highlight and copy the “Location” link (Ex: http://www.spooledupaz.com/picture.jpg)
6. Now click the “IMG” button on top of the thread editor and paste your link in between the tags.
7. Your link should now look like [img]http://www.spooledupaz.com/picture.jpg[img]
8. Finish editing post and press submit

See Also:

How to resize a picture
Im trying to upload an image and its not working
Embed video in a forum thread