Legacy ImageMagick Discussions Archive

Platform: Ubuntu 16
ImageMagick Version: 6.7.8-9

I have several large images i need to turn into one gigantic image.

Currently i've been testing the montage command with 4x 40,000 x 40,000 Images tiles in a 2x2 grid (so resulting output is 80,000px square) using the command:
I have 27GB of RAM on the AWS instance i'm working with, and IM seems to top out at 90.6% usage of this with low CPU usage (6-10%). It's been working for about 2 hours now.

Is there a better and faster way to achieve this?

Many thanks for your time

You don't have enough memory, so IM will cache pixels on disk, which is slow.

Your images are 8 bits/channel, so you don't need Q16 IM. If you are not using Q8, I suggest you do so, as that will halve memory usage.

I expect v7 would be better still, not storing the alpha channel.

More specialist tools may be quicker, eg jpegtran then pnmcat.

Thank you very much! I'll test out these options and update with further details.