Recently, my brother tried using Photoshop's generative fill to expand an image of some barren mountains in CA into a panorama. It did a superb job. My brother's suspicion, however, is that because the area is frequently photographed and shares many characteristics with other frequently photographed places, it was good match to the training set.
So, I tried an image that is less likely to match things in the training set, and generative fill failed miserably.
Here is the original shot. I took this with a drone last summer near Williamstown MA.
I first tried generative fill on the right hand side, but forest is an easy subject, it didn't fail badly at first glance, despite a few weird sections. So instead I first cropped a bit from the right, yielding this:
Then I did generative fill, just once:
What it produced was blurry, which fits with one thing Tim Grey wrote: presently, it can handle only low resolutions, and I fed it a relatively high-resolution image. That’s hardly the biggest problem, however. Take a look at the following, which is a crop of just part of the filled area. It’s full size if you click on the link.
The biggest problem is that the buildings look like they were painted by someone on powerful psychedelics. Some are merely distorted, but some appear to be a hodge-podge of elements from different buildings. The road is garbled and ends in a weird way, and if you follow it to the bottom end, you will see a bunch of random odd shapes.
I tried one last thing. I created the image above using the standard technique: expand the canvas and then select the expansion and a very small slice of the extant image. This time, I selected more of the extant image, including the road and some of the buildings. The result was different but equally bad:
Dan