When I post the picture to the blog, the size of the image display is limited by the size of the blog. But when you click on the image, then the blog is supposed to interpret that as "show me the image in it's original size or as close to that as you can manage." So the blog does just that.
The first image is a fairly small picture. When you click on it, it expands to the full size of the image--but that it still probably smaller than your screen, if you are displaying on a full-sized monitor.
it it completely fills the screen from top to bottom (because it is taller than it is wide).
The third image--the neighborhood--is also very large, this time wider than it is tall. So it fills the screen fully in the horizontal dimension, to the extent allowed by the blog software. The true size of the image is enough to cover three or four large screens.
And just to round out the picture, here is a very small image. When you click on it, it shows the full image--but that image is not big enough to fill anymore of the screen than the version shown here.
Note also that the blog automatically offered you (across the bottom of the screen) a slide-show option for all of the pictures in this post. I didn't have to tell the blog to do that, it just does it automatically.
And that, dear Kate and Amm, is how image display is supposed to work on a blog. There are many variations on this theme, but the general principles are that:
a. The size of the original image is not very relevant
b. "Version1" is posted in a small format, so people can see it "in line" with the blog itself.
c. Clicking on the image results in "Version2," which is the original image displayed in as large a format as the blog software allows.