At the bottom of the screen you will see the "Quick Reply" box. Below it is a rectangular button "Full Editor & Preview." Click on that.
The box now becomes "POST A REPLY" moving up on the screen. Below the box to the left are two tabs: "Options" and "Attachments": click on "Attachments."
Under the blue/gray area of the "Attachments" tab is a rectangle "Add files"; click on that.
Your PC or MAC files should open, whereupon you have to locate your photo by its name and double click on it"
After you double click a wide rectangle with "FILENAME" "FILE COMMENT" "SIZE" AND "STATUS" WILL APPEAR. (
For example, I uploaded a file named <Kilroy.jpg>)
Back up in the "POST A REPLY" box, click on where you want the file to appear.
Then move your pointer back down to the rectangle with "Place inline" and click.

- Kilroy.jpg (46.02 KiB) Viewed 10803 times
Your photo appears.