gazebo usage of textures / pictures

edit

I am trying to build a model of robot arm in simulation with checkerboards on it for image recognition. For this I use the simple arm model. Is there somewhere a good description of all the possibilities of urdf / gazebo models? Because I found from a presentation that you can use for instance patterns:

 <material name="pattern">
    <texture filename="package://roscon_urdf/logo.jpg"/>
</material>

But I could not find this back in the documentation..it did not load either:

 Warning [parser.cc:458] XML Attribute[name] in element[material] not defined in SDF, ignoring.
Error [parser.cc:566] XML Element[texture], child of element[material] not defined in SDF. Ignoring.[material]
Error [parser.cc:557] Error reading element
Error [parser.cc:340] Unable to parse sdf element[gazebo]
Error [parser.cc:299] parse as old deprecated model file failed.
Error [World.cc:1099] Unable to read sdf string
 

The material script line from the simple_arm was replaced with the code above. Loaded with

 rosrun gazebo spawn_model -file simple_arm.model -gazebo -model box