There are 2 ways to add pictures
#1
Upload the picture to The Garage Journal
1 First you need to go to the Advanced section of your post, Just click Go Advanced
then you will see this
2 Then click on Manage Attachments in the Additional Options section at the botom
This Window will open
3 Click Choose File and navigate to your picture on your computer, then click Upload and it will add it to your post.
#2
The other way is to use a image hosting site to upload the picture to
I use
http://imgur.com/
If you go there you can make an account to keep all your pictures
There you can Click upload pictures and it will give you links to put in your post, you will use the BBcode link.