The Preview feature, when enabled allows displaying the user file list in Thumbnail View mode, for most popular image, document and video file formats.For documents, a thumbnail image of the 
first (usually title) page is rendered, for videos, 10 slides evenly sampled along the duration time.\\
[{Image src='preview_main.jpg' width='1440' height='..' align='left' style='..' class='..' }]
\\
!!Prerequisits:
\\
Thumbnails generation relies on widely used free 3rd party conversion utilities, either part of the host operating system ( qlmanage in case of Mac OS ), can be downloaded from either the OS apps repository ( Linux yum and apt), or as a standalone package from the maintainer's site ( Windows, all OS).\\
The Preview settings page has a dropdown selector list displayed dynamically based on the host OS platform, we'll display the available presets for image and video preview. In case of Windows, 
Linux the conversion utilities need to be deployed manually.\\
!Image and document files:
On __Linux__ platforms need to deploy __GraphicsMagick__ for image formats and also __Ghostscript__ for documents. On Debian based platforms the packages are readily available from the apt repository
%%prettify 
{{{
apt-get install graphicsmagick
}}}
/%
On Red Hat/CentOS and usually other RPM based distros, can be installed from the EPEL repository. Download the latest epel-release rpm from
%%prettify 
{{{
http://dl.fedoraproject.org/pub/epel/[your redhat version here]/x86_64/
}}}
/%
Install epel-release rpm:
%%prettify 
{{{
rpm -Uvh epel-release*rpm
}}}
/%
Install GraphicsMagick the package:
%%prettify 
{{{
yum install graphicsmagick
}}}
/%
Alternatively, can try to use __ImageMagick__ still, the __v6.x__ version line if available, is stable. The __v7.x__ version line however may not be.
%%prettify 
{{{
apt-get install imagemagick
}}}
/%
Ghostscript has been on all major Linux app repositories for long, can simply install it like
%%prettify 
{{{
apt-get install ghostscript
}}}
/%
On __Windows__ platforms will need to user GraphicsMagick mandatorily, for the recent versions of ImageMagick will not work with Java no more. There are options, either use the binary installer, or use the portable __.zip__ package and deploy it somewhere.\\ 
External links to maintainer's download page\\
\\
GraphicsMagick [http://www.graphicsmagick.org/download.html|http://www.graphicsmagick.org/download.html]\\
Ghostscript    [https://ghostscript.com/releases/gsdnld.html|https://ghostscript.com/releases/gsdnld.html]\\
\\
On __Mac OS__ platforms usually don't need to do nothing, the conversion utility is readily available, need to use the __qlmanage__ preset, it will work out of the box. 
\\
\\
!Video files\\
 On __Linux__, need to install __ffmpeg__ from the official app repository, depending on the distro, with apt, yum or dnf, like
%%prettify 
{{{
apt-get install ffmpeg
}}}
/%
\\
On __Windows__ need to download from the maintainer either the binary installer and run it, or the portable __.zip__ package then unzip it somewhere on the host.
External link to maintainer's download page:
\\
\\
FFmpeg: [https://ffmpeg.org/download.html|https://ffmpeg.org/download.html]\\
\\
On __Mac OS__ platforms usually don't need to do nothing, the conversion utility is readily available, need to use the __pcastaction__ preset, it will work out of the box.
\\
\\
!!Setting it up:
\\
[{Image src='preview_config1.jpg' width='1440' height='..' align='left' style='..' class='..' }]
\\
!Heading 2 title
Holding down the Alt key while click the Add Folder button allows adding remote items (FTP://, SMB3://, etc.)

So the top half of the window in general you don't touch or change anything.  Just use the preset menu.  The bottom half of the window, you specify directories that CrushFTP should monitor for new files.  When it sees a new file, it generates a thumbnail for that file.

You can also have thumbnails generated for movie files.  OS X has a built in method for doing this, other OS's can use other utilities such as FFmpeg.  Still frames will be grabbed out of movies and made available as the mouse hovers over the icon.

[attachments|preview2.png]

The WebInterface with previews being generated may look something like this.

[attachments|webinterface_folders.png]