It is clearly visible that the extend part wasn't part of the picture. Do you have any clue how I can fix this? I'm just trying to let the image look like it has never been extended, so remove of the line and such in the middle. How can I do this in Photoshop? I'm not sure what terms to google for.
I've been playing around with Content Aware Scale after being inspired by this question, and have what I think is a great solution, quite different from my first, and an awful lot easier! A one minute solution.
Draw a rough selection around the car, I simply used the Polygonal Lasso
In the Channels palette click the "Save selection as channel" button
Hit "Edit" > "Content-Aware Scale"
On the top bar, under "Protect" select the Alpha channel (Alpha 1)
Drag the handle to scale the image, noting that the car is not distorted at all.
I was very pleased to extend my knowledge of content aware scaling, and I think the result is basically flawless:
The image here is by no means perfect, but I can tell you how I achieved it in two or three minutes, and hopefully you can use my notes as a guide to get it right (in half an hour+ haha):
Create new layer using as much of the land to the right of the car
as you can get
Delete the equal portion from the main image
Move the new section of land under the main image, move it to the
right so that it fills the gap (currently looks terrible)
Use a combination of content aware scaling, persepctive transform
and regular transform to shape it to fit..so that the rails line up
I never could get the lower rail and the top rail correct at the
same time, so in the end I made a new layer, and put a small section
of green along the top rail to line it up.
The key part, apply a layer mask to the main image and gradient
blend the two layers together, then a bunch (and it would take a
bunch more to finish it) hand adjust with mask blending, cloning,
dodging - all of it! haha. The sky to the upper right is particularly tricky. I might think about replacing that entire section with sky from elsewhere in the image.
I would do it in a partial way. So, first of all, let's copy upper part of our picture and bring it to the right of our workspace, but remember to put the part of an image on the original (as you can see on the picture). Also, we have to to fit the "lines" of our copy part and the background.
Same story for the lower part.
Now switch to the upper copied layer, take the eraser tool with small soft brush and delicate erase left edge of copied picture. You should see then something like on the picture below.
Same story for the lower part. I'm not that good with Photoshop, but you can improve the effect by Clone Stamp Tool, or Smudge Tool if you like.
Flip a copied slice horizontally and apply vertical skew. The seam has no color jump because the extension is the original mirrored. Also there's nothing remarkably stretched horizontally nor bendings on the road surface details.
Fade some detail with cloning to hide it's mirrored. You can also add an adjustment layer which have gradient layer mask.
Here some cloning is applied and the railing has got brightness adjustment. The layers were merged to keep things simple:
Filter > Vanishing Point.... You draw in the perspective grid(s) and then either paste in images or use the clone stamp tool.