Left/Right columns with background and margin

The link is joomla.bcmarburg.de

If you look at the left column I would like to have the follwoing for modules, there is between the modules with a flexible background image a margin which shows the overall template background.
Tha margin shall be bewteen every module I add.

You can set bottom padding of modules in left column and bill that empty space with background image, something like this:

.column_left .moduletable{
padding-bottom:20px;
background-image:url(....);
background-repeat:none;
background-position:center bottom;
background-size:contain;
}

make sure pattern image is equal in height to padding-bottom and to be large enaugt in width

I put in template_css.css
the following code

.column_left .moduletable{
padding-bottom:20px;
background-image:url( www.joomla.bcmarburg.de/BCMarburg/images...BBall_back_small.png );
background-repeat:none;
background-position:center bottom;
background-size:contain;
}

the link to picture hasn't changed but it doesn't show the background anymore. The modules are in position left.
Don't know why the picture is not found the background is 235 in width and 161 in height.
Dont know why
1. it doesn't show any background anymore
2. whether the background size is correct

I checked and changes in template_css.css had no effect on anything on the background in modules but putting a hard link in template_css.php would show the background I sent.
Do I have to add your code in template_css.php then?

Clck on a link from post #29087 you will end up at not found page. So eater path is incorrect or image does not have read permission for public.

Can find post #29087 via search function could please send the link. There is no access denied on the picutre