php imagecopyresized vs imagecopyresampled vs imagecopy pros/cons
imagecopyresized will copy and scale and image. This uses a fairly primitive algorithm that tends to yield more pixelated results.
imagecopyresampled will copy and scale and image, it uses a smoothing and pixel interpolating algorithm that will generally yield much better results then imagecopyresized at the cost of a little cpu usage.
imagecopy will copy but will not scale the image.