Thx so much Guys!
First of you click Attachment and other options you will find that below the text box then you click Choose file then you Click the picture you want to upload then Post it Hope I helped :D
Your question is a bit vague, do you mean:
1. How to attach a picture to the forums
A. Skyrun02 has helped you how to attach a picture to forums.
B. You may also use the IMG tag
[img]link of your picture[/img]