The first time I saw a plein air painting incorporated into the surrounding landscape in that way was many years ago when someone took a photo of a painting I was working on outside (above). This person lined up some of the major lines in the painting with the lines in nature behind the panel and thought it was very clever. At the time I was mildly annoyed with the image as I thought it would confuse people into thinking that it somehow related to sight-size.
As it turned out, I was right.
A few years later when we all started carrying decent quality cameras around in our telephones, I started regularly posting my paintings to social media directly from the field. Usually I took a photo of my painting with the actual scene on one side, so students who follow me could see my decisions by comparing the two. On a few occasions though, something would happen where my view would be obscured when I was finished and I would take the photo with the painting covering the scene. I would also align some of the lines so that the painting and the background appeared to merge.
One example of this is the painting below, where a tour group arrived and parked themselves in the path just behind my panel. As it was lunchtime, and I didn’t want to wait for them to leave, I used the painting to block them from the view.
This has nothing to do with sight-size though. In the photo above, you can see how the painted bulge of the tree (1) is completely different in size from the actual shape in nature (2). This is because, in order to get the lines to line up, I’ve had to pull the camera back away from the painting. When I did the painting my viewpoint would have been closer, and the two shapes would have been the same size. (See my sight-size video on YouTube for further clarification).
All I’ve really done is moved the camera until some of the major lines in my painting align with the same lines in the actual scene. I even had to tilt the camera away from the panel a bit to get it to work.
This has been a bit long-winded, but I just wanted to say that these aligned photos have nothing to do with sight-size. Any artist working outside can do them, with any technique or medium. Having compressed, naturalistic values will help with the illusion, but I’ve seen some wonderful examples of very stylized work doing the same trick. Just move the camera until a few important shapes line up with the view behind.