Image Transforms adding white to edges of image I have my image transforms set to crop centre-centre with quality 100, but for some reason the images that are rendered have a high change of having 1 or 2 pixels of white added to at least one set of parallel sides.

See below for an example of what is being output (black background added after the fact for emphasis):



The original image was a JPG with no white border. As far as I can tell, the issue is most prevalent when trying to crop in only one direction. For example, the the image above should only be being cropped on the top and bottom, as the width of the original is the same as the width of the outputted image.

Has anyone else come across this issue? If so, is there a fix?

Running locally on MAMP with PHP 5.6.10, using GD. Craft Pro 2.4.2679
As @BradBell says, using Imagick fixed this for me.
Following https://stackoverflow.com/a/16154605/662826 I uncommented the Imagick extension, reuploaded and the compression was much better and white line gone.