Use the little paperclip icon for "Attachments".
Then "Choose File" to find the picture on your computer.
Click the "Upload" button and wait for it to show in "Current Attachments".
Close that small window and hit the paperclip icon one more time.
Select that filename, an viola.
Note: The orientation of the photo from the original camera will determine whether it is right-side up. ie your camera has a default orientation. That is the way you should always take pictures for upload.