use Image::Magick;
  ...
  # Check and change image height if necessary
  my ($height,$width);
  ($height,$width) = $image->GetAttribute('height','width');
  if ( $height > 300 ) {
    my ($newheight,$newwidth);
    $newheight = 300;
    $newwidth = ($width*$newheight)/$height;
    $image->Scale('height'=>$newheight,'width'=>$newwidth);
  }
  
  # Check and change image width if necessary
  ($height,$width) = $image->GetAttribute('height','width');
  if ( $width > 250 ) {
    my ($newheight,$newwidth);
    $newwidth = 250;
    $newheight = ($height*$newwidth)/$width;
    $image->Scale('width'=>$newwidth,'height'=>$newheight);
  }

##</code><code>##

  # Adjust Resolution if necessary
  $image->SetAttribute('units'=>'PixelsPerInch');
  my ($xrez,$yrez) = $image->GetAttribute('x-resolution',
'y-resolution');
  if ($xrez > 72 || $yrez > 72) {
    $image->SetAttribute('density'=>'72x72');
  }

##</code><code>##

x-resolution is 300
y-resolution is 300

##</code><code>##

x-resolution is 72
y-resolution is 72