The documentation for Image::Thumbnail shows the following usage:

use Image::Thumbnail 0.65;
 
# Create a thumbnail from 'test.jpg' as 'test_t.jpg'
# using ImageMagick, Imager, GD or Image::Epeg.
my $t = new Image::Thumbnail(
        size       => 55,
        create     => 1,
        input      => 'test.jpg',
        outputpath => 'test_t.jpg',
);

# Create four more of ever-larger sizes
for (1..4){
        $t->{size} = 55+(10*$_);
        $t->create;
}
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I don't see any call to ->create in your code. Did you forget that call?

Update: Now I see - create => 1 is supposed to automatically create the thumbnail. If you use the automatic way, you won't get access to the error diagnostics, so I would look at the manual way first, to see the potential error messages:

my $t = new Image::Thumbnail(
        size       => 55,
        create     => 1,
        input      => 'test.jpg',
        outputpath => 'test_t.jpg',
);

$t->create;

print "Errors  : " . $t->{error, "\n";
print "Warnings:" . $t->{warning}, "\n";
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Upon reading the source code, it seems as the module does not actually set up those fields in most situations.

Solved by using module Imager within this code

#!/usr/bin/perl
use warnings;
use strict;
use Image::Thumbnail;

my $imgdir=  "/var/www/upload";

createImageMagickThumb('testFileUploadAndThumb.jpg');


sub createImageMagickThumb {

    my  $filename = shift || '';
    print "file name : $filename\n";
    print "file directory $imgdir\n";
    my $t = new Image::Thumbnail(
        module     => 'Imager',
        create     => 1,        
        size       => 100,
        input      => "$imgdir/$filename",
        outputpath => "$imgdir/thumb.$filename",
    );
    print "input      => $imgdir/$filename\n";
    print "outputpath => $imgdir/thumb.$filename\n";
}
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