/home/fred/Desktop/root3/pages/giants/template_stuff/aimages/Screensho
+t from 2014-08-21 13:10:18.png has filesize of 250625 bytes or 244.75
+09765625 k
file is /home/fred/Desktop/root3/pages/giants/template_stuff/aimages/S
+creenshot from 2014-08-21 13:10:18.png
ratio is 2.39951937806373
/home/fred/Desktop/root3/pages/giants/template_stuff/aimages/Screensho
+t from 2014-09-25 17:14:08.png has filesize of 166140 bytes or 162.24
+609375 k
file is /home/fred/Desktop/root3/pages/giants/template_stuff/aimages/S
+creenshot from 2014-09-25 17:14:08.png
ratio is 1.59064797794118
/home/fred/Desktop/root3/pages/giants/template_stuff/aimages/Screensho
+t from 2014-08-21 13:22:42.png has filesize of 81126 bytes or 79.2246
+09375 k
/home/fred/Desktop/root3/pages/giants/template_stuff/aimages/zbears.jp
+g has filesize of 872877 bytes or 852.4189453125 k
file is /home/fred/Desktop/root3/pages/giants/template_stuff/aimages/z
+bears.jpg
ratio is 8.35704848345588
/home/fred/Desktop/root3/pages/giants/template_stuff/aimages/. has fil
+esize of  bytes or 0 k
/home/fred/Desktop/root3/pages/giants/template_stuff/aimages/.. has fi
+lesize of  bytes or 0 k
/home/fred/Desktop/root3/pages/giants/template_stuff/aimages/yjj.jpg h
+as filesize of 237182 bytes or 231.623046875 k
file is /home/fred/Desktop/root3/pages/giants/template_stuff/aimages/y
+jj.jpg
ratio is 2.27081418504902
[download]

I'm pretty close on this one now. I know by what amount I want to reduce filesizes to. The syntax I relied on doing it bash style was a percentage. I'm still looking for that option. For what I'm doing right now, I don't want to bias the shapes of the things I post. I handle their shapes with the css. This is what I have now:

sub resize_images  {
use 5.010;
use Path::Class;
use Image::Magick;

my ($rvars) = shift;
my %vars = %$rvars;

$target = 100; 
$bias = 2; 

opendir my $hh, $vars{to_images} or warn "warn  $!\n";
while (defined ($_ = readdir($hh))){
  my $image = Image::Magick->new;
  my $file = file($vars{to_images},$_);
  $image->ReadImage($file);
  $x = $image->Get('filesize');
  my $k = $x/1024;
  say "$file has filesize of $x bytes or $k k";
    if ($k>$target){
      say "file is $file";
      my $ratio = $k/($target+$bias);
      say "ratio is $ratio";
    }  
}
[download]

It looks like the only way to use resize is to use the command line. I don't know how to make that happen with perl driving the logic other than through a system command followed by some script you've written. That's what I attempt to do here, but I seem to be hung up on a printf statement. Why is the %s not working in this printf call? I can see on my terminal that the loop is loading all the images in the directory, and that the logic for entering into the inner control seems to work, that is filesizes less than the target value are ignored, which gets rid of . and .. too. What follows is the routine followed by the helper script it creates.

sub resize_images  {
use 5.010;
use Path::Class;
use Image::Magick;

my ($rvars) = shift;
my %vars = %$rvars;

$vars{"target"}= 100;
$vars{"bias"}= 2;
$vars{"helpscript"}= "helper1.sh";
my $file2 = $vars{"helpscript"};
my $path = $vars{"to_images"};
open( my $fh, ">", $file2 )
  or die("Can't open $file2 for writing: $!");
my $cd = "cd $path \n";
print $fh $cd;
my $ls = "ls -lt >>text1.txt\n";
print $fh $ls;

opendir my $hh, $path or warn "warn  $!\n";
while (defined ($_ = readdir($hh))){
  my $image = Image::Magick->new;
  my $file = file($path,$_);
  $image->ReadImage($file);
  $x = $image->Get('filesize');
  my $k = $x/1024;
  say "$file has filesize of $x bytes or $k k";
  if ($k>$vars{"target"}){
    say "file is $file";
    my $ratio = $k/($vars{"target"}-$vars{"bias"});
    say "ratio is $ratio";
    my $percent = 100/$ratio;
    say "percent is $percent";
    my $mogrify_spec = "mogrify -resize %2.2f\% %s\n";  
    printf $fh $mogrify_spec, $percent, $file; 
    #printf $fh "file is $file\n"; 
    }  
  close $fh;
  }
}
[download]

$ cat helper1.sh
cd /home/fred/Desktop/root3/pages/raiders/template_stuff/aimages 
ls -lt >>text1.txt
mogrify -resize 40.04%s
$
[download]

The "\%" in your $mogrify_spec isn't doing what you think - it results in the format string containing a "%". Even if you put a backslash in the string via "\\", that's not what you want:

$ perl -wMstrict -e 'print "foo %2.2f\% %s\n"'
foo %2.2f% %s
$ perl -wMstrict -e 'printf "foo %2.2f\% %s\n", 40.04, "bar"'
foo 40.04%s
$ perl -wMstrict -e 'print "foo %2.2f\\% %s\n"'
foo %2.2f\% %s
$ perl -wMstrict -e 'printf "foo %2.2f\\% %s\n", 40.04, "bar"'
foo 40.04\%s
[download]

See sprintf: The way to escape a percent sign in a format string is "%%":

$ perl -wMstrict -e 'print "foo %2.2f%% %s\n"'
foo %2.2f%% %s
$ perl -wMstrict -e 'printf "foo %2.2f%% %s\n", 40.04, "bar"'
foo 40.04% bar
[download]

(I'm a little surprised Perl doesn't warn about this, because there are several other warnings about bad format strings and such...)

It looks like the only way to use resize is to use the command line.

The following works for me. The API is documented here: http://www.imagemagick.org/script/perl-magick.php

use Image::Magick;
my $img = Image::Magick->new;
my $rv = $img->Read('/tmp/foo.jpg');
die "$rv" if "$rv";
$rv = $img->Resize(geometry=>'50%');
die "$rv" if "$rv";
$rv = $img->Write('/tmp/bar.jpg');
die "$rv" if "$rv";
[download]