I started looking for the image. In my reply to you, it is above my typing. If you hit reply to my message, you will see a line of icons above the typing window. Third from the right is a tiny icon that looks like a picture frame. If you look very closely, you will see a tree in that frame. If you hover your mouse pointer over the icon, it will say "insert image".
That's as far as I can get you, having never even attempted to post a photo here before!
Edit: If you scroll down to "quick reply", you will see the line of icons. I assume they show up also if you are starting a new thread. The "insert image" icon is a couple to the right of the smiley icon.