@JPEG When you click an image, sometimes it opens over the whole window, while other times it overs only part of the window. I had trouble figuring out how to dismiss the image. At first it seemed like clicking the bar at the bottom of the image overlay was the way out, but that opens the toot in the right-most column. I finally discovered by accident that dragging the image down closes the overlay.
For what it's worth, I'd prefer it if the image opened in a new window, with a close button.