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<page xmlns="http://projectmallard.org/1.0/" type="topic" id="gthumb-thumbnails" xml:lang="oc">
<info>
<link type="guide" xref="index#reference"/>
</info>
<title>Thumbnail Sources</title>
<p>The browser window normally shows the thumbnails of the images
and movies in the selected folder. Generic icons for other files
(audio files, for instance) may also be shown.</p>
<p>You can select what types of files to show in the browser view
using the <guiseq><gui>View</gui><gui>Filter</gui>
</guiseq> dialog. The default is to show all media files (images,
movies, audio), but this can be made more or less
restrictive.</p>
<p>The thumbnails may be generated by a number of different
methods. <app>gThumb</app> will first check for existing thumbnails in the
system cache.</p>
<p>If no cached thumbnail is found, and an image file contains an
embedded thumbnail (jpeg files generated by digital cameras
normally do), <app>gThumb</app> will attempt to use that. <app>gThumb</app> will
confirm that the aspect ratio of the thumbnail is similar to that
of the main image, and ignore thumbnails that do not appear to
match the main image.</p>
<p>If that doesn't work, <app>gThumb</app> will attempt to load the entire
file and generate a scaled-down thumbnail.</p>
<p>Lastly, <app>gThumb</app> will use any system-defined scripts for
thumbnailing particular media types. For example, some systems
may use <app>mplayer</app> or <app>totem</app> or other movie viewers to generate movie
thumbnails.</p>
<p><app>gThumb</app> will save thumbnails to a system cache, to share them
with other applications. By default, Gnome systems prune cached
thumbnails when they are older than 180 days, or when the
thumbnail cache exceeds 512 MB. Technically-inclined users can
explore these settings with <app>gconf-editor</app>. See the
/desktop/gnome/thumbnail_cache/maximum_age and
/desktop/gnome/thumbnail_cache/maximum_size keys in particular.
Certain applications (like <app>F-Spot</app>) may automatically increase
these settings greatly.</p>
</page>
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