Get a Photobucket account and upload the images there, then copy the IMG code for the image you want to display in a thread and paste it via the "insert link" button in the "reply to thread" screen for example whenever you want to include an image in a post.
...or you may upload pictures directly to the forum. While writing your post choose advanced and you will see manage attachments button in the additional option box. You can upload pictures from your hard drive, system automaticly resizes if the file is too big. Now we are redy to see your balls