symfony - 500 internal server error - IOException: Failed to create media/cache/my_thumb with LiipImagineBundle -

i trying apply filter on image based on liipimaginebundle.

here steps:

1. installation through composer file adding line:

   "liip/imagine-bundle": "1.0.*@dev"

2. configuration of config.yml file adding these lines:

   liip_imagine:     resolvers:     default:         web_path:               web_root: %kernel.root_dir%/../web             cache_prefix: media/cache  filter_sets:     cache: ~     my_thumb:         quality: 75         filters:           thumbnail: { size: [120, 90], mode: outbound } 

3. declaration of bundle in appkernel.php:

   new liip\imaginebundle\liipimaginebundle(), 

4. testing bundle adding there line twig file:

   <img src="{{ asset('img/test.jpg') | imagine_filter('my_thumb') }}" /> 

but, no image displayed. generated html file contains:

<img src="http://localhost/tuto/web/app_dev.php/media/cache/my_thumb/img/test.jpg"> 

and in javascript console of browser, find error:

get http://localhost/tuto/web/app_dev.php/media/cache/my_thumb/img/test.jpg 500 (internal server error)

when try open link (with 500 internal server error), symfony throws error:

failed create /home/amine/netbeansprojects/tuto/app/../web/media/cache/my_thumb/img 500 internal server error - ioexception

i guess not have permission create following folder: /home/amine/netbeansprojects/tuto/app/../web/media/cache/my_thumb/img. in point of view, expectable since working on ubuntu.

to avoid problem, directly changed permissions on folder web through sudo chmod 777 -r web problem still same.

is there idea?

the problem solved. changed config.yml this:

    liip_imagine:         resolvers:         default:             web_path:                   web_root: %kernel.root_dir%/../web/imagine                 # imagine folder filtered images created!                 cache_prefix: tuto/web/imagine/media/cache                 # tuto folder of symfony application      filter_sets:         cache: ~         my_thumb:             quality: 75             filters:               thumbnail: { size: [120, 90], mode: outbound } 

and twig part, has been changed to:

<img src="{{ 'img/test.jpg' | imagine_filter('my_thumb') }}" /> {# img folder put images!#} 

my question is: possible change configuration of parameter cache_prefix in way replace tuto else in order have configuration works anywhere? asking question because avoid problems when hosting web site!

thanks...