Maybe you're aware of this already and did in two steps for a specific reason, but if you're not bothered about ordering you can make the montage in one step by making use of the ImageMagick MIFF format find /some/images/ -type f -iname "*.jpg" -exec convert -resize 256>x256> {} MIFF:- \; | montage - -tile 10x5 -geometry +0+0 -quality 72 /tmp/montage.jpg The ordering will be directory order as that's what find outputs in (or at least it does in my observation see also "ls -U").