I've found an interesting issue where under ImageMagick-6.0.7.1 I can resize an image and it remains 8-bit, however under ImageMagick-perl-6.2.8.0 resized images are written at 16-bit. I need this code to generate 8-bit thumbnails on both systems and I can't seem to find a way to force the 8-bit depth from within PerlMagick. As an example I wrote this script: 
#!/usr/bin/perl

use Image::Magick;

my $thumbnail = Image::Magick->new;
$thumbnail->Read("full.bmp");
$thumbnail->Write("full.png");

$thumbnail->Resize(width=>'200', height=>'150');
$thumbnail->Write("tn_200x150.png");

$thumbnail->Resize(width=>'100', height=>'75');
$thumbnail->Write("tn_100x75.png");

undef $thumbnail;

exec "file /home/mhenkel/*.png";

[download]
On the ImageMagick-6.0.7.1 it outputs: 
/home/mhenkel/full.png:       PNG image data, 240 x 294, 8-bit/color R
+GB, non-interlaced
/home/mhenkel/tn_100x75.png:  PNG image data, 100 x 75, 8-bit/color RG
+B, non-interlaced
/home/mhenkel/tn_200x150.png: PNG image data, 200 x 150, 8-bit/color R
+GB, non-interlaced

[download]
and the ImageMagick-perl-6.2.8.0 system: 
/home/mhenkel/full.png:       PNG image data, 240 x 294, 8-bit/color R
+GB, non-interlaced
/home/mhenkel/tn_100x75.png:  PNG image data, 100 x 75, 16-bit/color R
+GB, non-interlaced
/home/mhenkel/tn_200x150.png: PNG image data, 200 x 150, 16-bit/color 
+RGB, non-interlaced

[download]
Ideas? Suggestions?

In reply to Image::Magick Depth by Guildencrantz

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.