# 4k/scene115/000071.png
# sd/scene115/000071.png
# writes scene115.jpg
find 4k -name 'scene*' -maxdepth 1 | while read line ;do t=`ls $line | sort | tail -1`; echo $line; montage ${line/4k/sd}/$t $line/$t -tile 2x1 -geometry +0+0 ${line/4k\//}.jpg ;done