Probleme with parameter queue_size in image_proc node

edit

Hello everyone,

I try to change the size of the message queue in image_proc by raising the parameter ~queue_size in a roslaunch file:

<launch>
     .
     .
     .
  <node name="image_proc" pkg="image_proc" type="image_proc" ns="camera_pi"  output="screen" >
     <param name="queue_size" value="1" />
  </node>
</launch>

The parameter is raising correctly, it appears in rosparm list under the name : /camera_pi/image_proc/queue_size (seem correct to me ?). But this as no effect on the queue size of the node who remaining at the default size (5).

Any idea ?

Thanks

Edit : the image_proc node documentation, see the section 3.0.1 Parameters, and the source code can be found here