You should get a + sign with your cursor over the image when it first loads into your browser. Clicking on it will open it up full size where you do have to scroll to see the entire image.
As I was interested in seeing
detail,
scrolling is precisely what I wanted to do, with a larger image. It came up "full size" and I had the + sign momentarily. When I clicked a couple of times, the image did get bigger. So, I don't know how that worked, but I got what I wanted.
Where is this mural? With the enlarged image, you can almost see the creche behind the bushes.