Pictures or a tutorial

Seriously? ('Cuz I never know with you....)
OK then...
1. Have the Forum message that you're composing open.
2. Open a new window showing the contents of the folder where the photo is.
3. Now either:
a. Right-click on the photo, select Copy, navigte to the message at the location where you want to insert the photo, right-click again, and select Paste; or even easier...
b. Left-click on the photo
and hold it,
while holding move the curser to the browser icon in the program tray at the bottom of your screen (if you have it set up that way)...
...and hover there until the window with the draft message opens, move the curser to where you want to insert the photo, then release the left button. That's "click-and-drag."
There are probably other ways to do it too...