Please describe the problem:
The same bug has been reported for shared-mime-info 0.30 on debian (http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=486468)

What I have found is that .flv files have the mime type video/x-flv when shared-mime-info 0.30 or 0.40 is installed but there is no equivalent gnome thumbnailer - gconf-editor lists application/x-flash-video and video/flv under desktop/gnome/thumbnailers.

Fixed the problem here by installing a new thumbnailer schema for video/x-flv:

<gconfschemafile>
    <schemalist>

        <schema>
            <key>/schemas/desktop/gnome/thumbnailers/video@x-flv/enable</key>
            <applyto>/desktop/gnome/thumbnailers/video@x-flv/enable</applyto>
            <owner></owner>
            <type>bool</type>
            <default>true</default>
            <locale name="C">
                <short></short>
                <long></long>
            </locale>
        </schema>


        <schema>
            <key>/schemas/desktop/gnome/thumbnailers/video@x-flv/command</key>
            <applyto>/desktop/gnome/thumbnailers/video@x-flv/command</applyto>
            <owner></owner>
            <type>string</type>
            <default>/usr/bin/totem-video-thumbnailer -s %s %u %o</default>
            <locale name="C">
                <short></short>
                <long></long>
            </locale>
        </schema>

    </schemalist>
</gconfschemafile>

Steps to reproduce:
1. Clean out ~/.thumbnails
2. Navigate to a directory containing .flv files with nautilus


Actual results:
The .flv files are not thumbnailed but are assigned a text file icon

Expected results:
Thumbnails should be generated for the .flv files, which is what happened with shared-mime-info 0.23 installed.

Does this happen every time?
Yes

Other information: