Image auto-rotate issue - Imagick Fix (proposition)

Image auto-rotate issue - Imagick Fix (proposition)

In line:
>$this->im->extentImage(($expansion_factor*$geometry['width'])/2,($geometry['height']),0,0);

`$geometry['width'])/2` resolution is halved for performance/speed trade-off. Without this, the code is 4x slower due additional processing, and generally working on large images when extending canvas.

with /2 processing is only 50% slower then original code, which is acceptable.

Possibly, other more optimal solutions exists, but this is best I could think of with limited knowledge of Imagick.