#!/usr/bin/env perl
use strict;
use warnings;

my $dateiread = "/home/ni/OUTPUT/test.png";
my $dateiwrite = "/home/ni/OUTPUT/test2.png";
my $buffer;
my $zeichen;
my $bytes = 4;

open (my $handle1, "<", $dateiread); 
open (my $handle2, ">", $dateiwrite); 

while (my $zeichen = getc($handle1))
    {
    seek($handle1, -1, 1);
    read($handle1, $buffer, $bytes);
    if ($buffer =~ /IEND/g)
        {
        print $handle2 $buffer;
        exit;
        }
    seek($handle1, -3, 1);
    print $handle2 $zeichen;
    }
close ($handle1);
close ($handle2);