This simple program generates thumbnails of digital camera raw image 
files using libopenraw and GDK. It supports the same file formats as 
libopenraw (http://libopenraw.freedesktop.org/wiki/FileFormats).

This thumbnailer is designed to be small, lightweight and fast. It 
is primarily intended to be used with file managers (although it 
could easily be used by a photograph management program) and is 
used by thunar-thumbnailers.

Usage: raw-thumbnailer -i input_file -o output_file -s size 

raw-thumbnailer requires libopenraw, for which a SlackBuild script will 
be avaible at SlackBuilds.org