Originally posted by Wheatfield Extend the canvas to the size you want. Set the foreground colour to the sky colur and paint in the sky colour.
Use the patch tool to drag the final colour and texture into the area you've added.
The problem is that the sky colour is not exactly one colour and I think this might look unnatural.
I would do this in The GIMP or PSP:
1. Extend the canvas size and position the original image on the copy.
2. Make a rectangler section to cover the whole vertical strip you want.
3. Copy/Clone/Paste the selected stripe to the blank region on the right.
4. Use a Healing tool to smooth the boundary so there is no slight change in colour/brightness at the intersection.
If you shot this in raw and if you have a raw converter with a fine colour corrector, like SilkyPix or Pentax DCU (which use the SilkyPix engine), I'd also consider altering the sky colour. To me, it seems a little too green/not blue enough.
Dan