You will need 3 things:
- A connection to the internet. If you don't have this, well...then you're probably not
posting here.

- A picture (duh)
- An online hosting websites. I personally prefer
Photobucket, but there are other good sites, such as
Snapfish or
Flickr
The website itself will give you directions on uploading
pictures. Once uploaded, the good websites (such as Photobucket) will even give you the link that you need to post here. (If they do NOT, all you should have to do is surf to the picture you just uploaded, right-click on it and select "Properties", and then highlight the "Location (URL)" (under IE) or "Location" (under image properties) (under Firefox). Once it's highlighted, right-click on it and select "Copy.")
Once you have the location (it'll look something like
http://www.blah.com/blah/blah.jpg), you will come here, and in the actual post where you want to show the picture, you will type the following:
[ img]put your link here[/ img]
You will need to remove the space before each 'img' word - I put the spaces there so that the website doesn't accidentally interpret it as an actual image.
Hopefully this clarifies things. If you still need help, please feel free to ask.