if I can do it you can. Ill do it now step by step.
1.go to reply to thread.
2.scroll down below message box.
3.2nd box says attach files click manage attachments
4.a box opens it says upload file from your computer,or from URL
5.click browse and choose a pic from your computer
6. once you pick the pic hit open file
7. now hit upload.
8. now the pic is attached you can do 5 pics.
9. when you are done hit close window and submit reply
10. like so ( my red serpent star)