Here's one possible way to do what you want, if I understand your request properly.
The mix shader on the lower left is just the one that comes from the Images as Planes addon. That could just as easily be the direct Color out of the Image node. What I'm doing here is crushing the darker areas so that the image is mostly just the lights and the skyline. ...
The white spot in your render is just a reflection of your Point light.
To make it also visible in the Viewport, you have to enable your Scene Lights.
You seem a bit confused about using the Bump node.
If you're using it with a color image, add a color ramp to make it BW and to control the contrast.
There's no need for a Displacement node.
There is many possibilities to do separation, but also with so many limits, that make it almost nonsense.
First limit is 8bit depth of your JPEG, should be 32bit like Open EXR. 32bit gives you much wider color range (especially to separate sky).
Second limit is bouncing light that make it totaly impossible to separate all indirect light for re-lightning ...
Simple control of emission without affecting source appearence.
Quite surprised how light wrapped Sphere just from front direction.
But object is not lighted from front (black faces in center), because there is not any light behinde camera.
You can also use the image as World material mapped for Camera window (Texture ...
Good news! I managed to figure it out. I found this thread here, recreated the node map in the last picture on that thread, and lowered the emission strength so the villager wasn't blindingly bright.
Edit: Turns out replacing the Emission node with a Diffuse BSDF node works as well. Good to know.
The answer to my question in case anyone else runs across this problem, was the sort order of the images
Image 1 shows I clicked on the display icon
Then I changed the display mode from sort by date to name of the images.
Not sure why date order did not work, but because it was in the wrong sequence only one image was imported.
In image 2 you can see all ...
It appears that alpha channels no longer work with images stored in empties in Blender 2.8.
The workaround, which is probably a better solution, is to load the image as a material into a plane object. The scene then must be viewed with Viewport Shading either "Material Preview" or "Rendered", as the material will not be visible from "Solid" mode, as ...