my $blob = $image->ImageToBlob();
#now your image is in the scalar $blob and you can gzip it
#and write it out to file any way you can get to work
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The thing is, I think ImageToBlob() returns raw image data. As the file type is not even defined yet. It is normally defined on writing the image data to STDOUT:

binmode STDOUT;
$image->Write("gif:-");
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Could I write to a container like <CONTAINER> and from there print it out to STDOUT? I am asking this because I need to apply Gzip to the output to speed up the transfer of the image to the browser, therefore I need to have the image data in a variable.

It's not documented very well, but you can set the file type before you create the blob, with the "magick" option.

$image->Set(magick=>'gif');  #set it to any type that's IM legal
my $blob = $image->ImageToBlob();
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Here is a working proof.

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

my $image = Image::Magick->new(
   size => "600x600" );

$image->Read("xc:white");
$image->Draw(
   primitive => 'line',
   points    => "300,100 300,500",
   stroke    => '#600',
);

$image->Set(magick=>'gif');

my $blob = $image->ImageToBlob();

open(FH,"> $0.gif")or die "$!\n";
print FH $blob;
close FH;
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---

I'm not really a human, but I play one on earth Remember How Lucky You Are

$image->Set( magick      => 'png' );
$image->Set( compression => 'Zip' );
print $image->ImageToBlob;
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Thanks, you're completely right. Much easier to let PerlMagick do it self. I know this is subjective, but what's the best compression to use for JPEG images, esp map images? I already reduced the amount of colours to 256. Is JPEG2000 > JPEG? BZip, Fax, Group4, JPEG, JPEG2000, LosslessJPEG, LZW, RLE, Zip I know for GIF only LZW can be used, correct?

From Wikipedia's entry for JPEG 2000:

As of 2008, JPEG 2000 is not widely supported in web browsers...

JPEG is designed for photographs, so it's appropriate to use if your map has many color gradations, such as a relief map.

If you have a street map with lines and regions of constant solid color, GIF or PNG is likely better due to the lossless compression. Over-compressed JPEGs of this type of image look poor due to the artifacts from the lossy compression.