I have just been fooling around trying to solve the problem with copying and pasting images.

Try this:

1. Select the online image and right click "copy image"

2. Click the "Insert Photos" option (at top)

3. Left click inside the grey box

4. Press "ctrl and v" (paste) on keyboard

5. Click "Done" at bottom right

6. Bob's your uncle, I hope.

However, if you make a boo boo, you must "Cancel" the post and try again in a new "Reply". Trying again in the same reply will cause flooding.

That's how I posted the below image after I was unable to copy/paste the usual way.