imagecopyresampled

[Ryland]

If you figure out a way, I'd like to know it too. I can't think of a way to do it other than the way you described, cloning and cropping. Can the source image be cropped beforehand? Are the image sections all the same size? If you cropped it beforehand, you could just read in each section separately and resize it.

[magick]

Cloning and cropping should work efficiently. Cloning is light-weight since only the image attributes are copied. The pixel cache is not duplicated, instead we just reference the original image cache. We suspect you will get a speed-up with the pending ImageMagick 6.4.1-4 release. We took time out to improve a number of algorithms to speed them up both serially and on dual & quad-core processor systems.