Set Thumbnail file / Preview Picture

[Progi1984]

• http://www.aspose.com/docs/display/slidesnet/Creating+Slides+Thumbnail+Image
• OpenXML
  • https://msdn.microsoft.com/en-us/library/dd721893(v=office.12).aspx

By default, this folder contains the files app.xml (for application properties such as word count and program version) and core.xml (for document properties such as the Document Properties summary information like author and subject). Additionally, if you use the options to save a preview picture or a thumbnail for your document, you see a thumbnail image file in the docProps folder. For Word 2007 and Excel 2007, this will be a .wmf file and for PowerPoint 2007 it will be a jpeg file.

# http://cpansearch.perl.org/src/EXIFTOOL/Image-ExifTool-9.70/lib/Image/ExifTool/OOXML.pm
# process only XML and JPEG/WMF thumbnail images in "docProps" directory
next unless $file =~ m{^docProps/(.*\.xml|(thumbnail\.(jpe?g|wmf)))$}i;
# get the file contents (CAREFUL! $buff MUST be local since we hand off a value ref)
my ($buff, $status) = $zip->contents($member);
$status and $et->Warn("Error extracting $file"), next;
# extract docProps/thumbnail.(jpg|mwf) as PreviewImage|PreviewMWF
if ($file =~ /\.(jpe?g|wmf)$/i) {
    my $tag = $file =~ /\.wmf$/i ? 'PreviewWMF' : 'PreviewImage';
    $et->FoundTag($tag, \$buff);
    next;
}

• OpenDocument
  • directory Thumbnails
  • https://en.wikipedia.org/wiki/OpenDocument_technical_specification#Thumbnails_.28directory.29

<manifest:file-entry manifest:full-path="Thumbnails/thumbnail.png" manifest:media-type="image/png"/>