You have to know two things:

1. the mime type of the image
2. the size of the image

Then it's all a matter of sending the correct HTTP header, and then simply printing the image.

use CGI qw(:standard);

my $mime_type = 'image/jpeg';
my $size = length($data); # Assuming $data contains your image

print header(
    -type => $mime_type,
    -Content_Length => $size,
);
print $data;
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Now, how you get the mime type and the image is up to you, it could be from a database or from a file on disk.

use CGI;
my $img = CGI->new->param('name');
my ($type) = (lc($img) =~ m/([^\.]+)$/s);
my %switch = qw/jpg jpeg tif tiff/;
$type = $switch{$type} if exists $switch{$type};
print "Content-type: image/$type\n\n";
open(IMG,"</path/to/files/$img");
binmode(IMG); binmode(STDOUT);
print while <IMG>;
close(IMG);
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Thanks.

I worked it out in the end. Its head slappingly simple Thanks everyone Heres the finished script:-

#!/usr/bin/perl -w
=comment
    This is for customer proofs NOT cam/management proofs
    Responds to a request for a customer proof image from the internet
+.
    Reads the requested image from disk and serves it back to the brow
+ser.
    Used to serve private images that are not on the apache tree in re
+sponse to a browser request to
    fill an image tag eg
    <img src=\"http://www.caralan.com/cgi-bin/customer_image_server.cg
+i?load_image=cust__stevecaralancom1129266425_00.gif\"  border=\"0\" a
+lt=\"\">
=cut


use strict;
use CGI;
#use File::Copy;
#use Tie::File;
#use Fcntl qw( :DEFAULT :flock );
use steves_general_functions;

my $mycgi = new CGI;
my $imagedata = "";


my $load_image  = $mycgi->param( "load_image" );
   $load_image = &gen_wash_input($load_image, "filename");   

my $proof_folder = "/caralan_com/system/proofing/customer_proofs/proof
+s_out/";

my $imagefile = $proof_folder . $load_image;


  #Set mime type for returned binary dump
  if( lc(&gen_get_extension_from_path($imagefile)) eq ".gif"){
    print "Content-type: image/gif\n\n";
  }
  if( lc(&gen_get_extension_from_path($imagefile)) eq ".jpg"){
    print "Content-type: image/jpeg\n\n";
  }
  if( lc(&gen_get_extension_from_path($imagefile)) eq ".tif"){
    print "Content-type: image/tif\n\n";
  }

  #Slurp binary image data from diskfile
  {
    local( $/, *IMAGEFILE ) ;
    open( IMAGEFILE, $imagefile );
    $imagedata = <IMAGEFILE>;
    close IMAGEFILE;
  }

  #Send binary dump to browser
  print $imagedata;
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