Using skew (in Photoshop or another graphic program) is an easy way to correct (some of) the lens distortion so obvious in many pictures.
In the left picture both buildings are in my opinion too much 'pressed' towards the middle.
To correct this (moderately), I first enlarged the canvas (left and right the same amount), then selected the full original picture, activated the skew function and stretched the upper left and upper right corner horizontally until I was pleased with the result.
I am sure there are other and better ways to achieve the same or better results but this works fast and fine for pictures with no or few details in the corners of the picture (as it is stretched the most there). All feedback welcome.