ImageMagick crop huge image

Question

I am trying to create tiles from a huge image say 40000x40000

i found a script on line for imagemagick he crops the tiles. it works fine on small images like say 100

Answer 1

libvips has an operator that can do exactly what you want very quickly. There's a chapter in the docs introducing dzsave and explaining how it works.

It can also do it in relatively little memory: I regularly process 200,000 x 200,000 pixel slide images using less than 1GB of memory.

See this answer, but briefly:

$ time convert -crop 512x512 +repage huge.tif x/image_out_%d.tif
real    0m5.623s
user    0m2.060s
sys     0m2.148s
$ time vips dzsave huge.tif x --depth one --tile-size 512 --overlap 0 --suffix .tif
real    0m1.643s
user    0m1.668s
sys     0m1.000s