Sorry for the delay - have been snowed, and then forgot!
Let's see what happens if I try the same process with your link: ah, same error......
OK, I figured it out (and yeah the error message ain't so helpful!) - the URL you posted for your image doesn't fetch the actual image, but instead a web page which includes the image.
If you load the image itself from that web page, you'll find this (or similar) URL:
https://lh4.googleusercontent.com/e...qKnoLuDdwrbsTdwSdRJPfuXOJF7B4yLpIw=w1920-h983 (NB: this is potentially not a permanent URL anyway, knowing Google) which works perfectly with the insert-image-by-URL button: