Pretty simple really. After you hit the REPLY button, just press the UPLOAD FILE button at the bottom of the message box, select your file/pic and wait a few seconds. You'll see what to do next.
Easy peasy!
Click on "upload a file" at the bottom right of comment box.
Go to the location of the photo file on your computer and click (highlight file) then click "open".
Choose if you want a thumbnail or full image (I chose thumbnail here) and you be DONE!!!
Pretty simple really. After you hit the REPLY button, just press the UPLOAD FILE button at the bottom of the message box, select your file/pic and wait a few seconds. You'll see what to do next.