Installing perlmagick was what I needed. I've written a routine that iterates through the images folder, but I fail to create and assign the object correctly:

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

my ($rvars) = shift;
my %vars = %$rvars;
opendir my $hh, $vars{to_images} or warn "warn  $!\n";
while (defined ($_ = readdir($hh))){
  my $image = Image::Magick->new;
  $image->ReadImage($_);
  $x = $image->Get('filesize');
  say "$_ has filesize of $x";
}
}
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Output:

Screenshot from 2014-08-21 13:10:18.png has filesize of 
Screenshot from 2014-09-25 17:14:08.png has filesize of 
Screenshot from 2014-08-21 13:22:42.png has filesize of 
zbears.jpg has filesize of 
. has filesize of 
.. has filesize of 
yjj.jpg has filesize of
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Fishing for tips....

You need to prepend the directory to the filename (see readdir), and you can check if the read was successful:

my $dir = $vars{to_images};
...
my $err = $image->ReadImage("$dir/$_");
warn "$err" if $err;
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Also, might be better to filter out the non-image files before passing to Image::Magick.