make-thumbs.sh

#!/bin/bash
# create thumbs

rm .thumb/*-thumb.jpg # 2>/dev/null

(for f in *.jpg ; do
    b=`basename "$f" .jpg`;
    s=`identify "$f" | cut -d" " -f3 | perl -nle '
      ($width,$height) = split 'x';
      die "bad size" unless $width && $height;
      ($max_w,$max_h) = (64,128);
      $k_w = $max_w / $width;
      $k_h = $max_h / $height;
      # https://fastapi.metacpan.org/source/SHERZODR/Image-Resize-0.5/Resize.pm
      $k = ($k_h < $k_w ? $k_h : $k_w);
      $new_w = int($height * $k);
      $new_h = int($width * $k);
      print $new_w.'x'.$new_h
    '`;
    t=".thumb/$b-thumb.jpg" ;
    convert -resize $s -quality 50 "$f" "$t" 1>&2
    if [[ -f $t ]] ; then
        printf 'AddDescription '"'"'<a href="%s"><img src="%s" data-size="%s"></a>'"'"' %s\n' \
                                         "$f"            "$t"             "$s"        "$f";
    fi
 done) | tee .htaccess