Effective Image Manipulation
The left and right windows are, respectively, the left and right mirror reflections of the centre window.
It is a very simply manipulation, but only so as it is digital.
It allows me a more effective presentation of the original picture. And if the original have been less than 3MP, now you have three times as many pixels.
A designer still have the single window if he needs to, but it looks better in a row of three almost identical windows.
Photo credits: Lawrence Wee.