This documentation refers to apache_image_resizer version 0.0.9
Place the following snippet in your Apache config:
<IfModule mod_ruby.c>
  RubyRequire apache/ruby-run
  RubyRequire /path/to/apache_image_resizer
  # or
  #RubyRequire rubygems
  #RubyRequire apache/image_resizer
  <Location /image_resizer>
    SetHandler ruby-object
    RubyHandler "Apache::ImageResizer.new"
  </Location>
  <Directory /path/to/images>
    ErrorDocument 404 /image_resizer
  </Directory>
</IfModule>
Expected filesystem layout and URLs:
/images/bla/original/blob/blub_42-23.jpg
 `-- base
        `-- prefix
            `-- source directory
                     `-- path --------->
/$BASE/$PREFIX/r42x23/$PATH
               `-- directives
Jens Wille <jens.wille@gmail.com>
Copyright (C) 2011-2012 University of Cologne, Albertus-Magnus-Platz, 50923 Cologne, Germany
Copyright (C) 2013 Jens Wille
apache_image_resizer is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
apache_image_resizer is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more details.
You should have received a copy of the GNU Affero General Public License along with apache_image_resizer. If not, see <www.gnu.org/licenses/>.