[j_cso]

Version: 5.6.0 . 23250 (Ubuntu)

To reproduce: 
  file...open a .png file.  Image appears as expected
  file...save .rdk
  file...open the .rdk you just created

Now there's just a gray rectangle where the image should be.  (Also does this with .jpg)

[Albert]

This behavior is expected unless you activate the option to save texture data and image data. You can enable this by following these steps:

1. Right click your station
   
2. Check the option Save texture data
   
3. Check the option Save image data
   

This setting is saved with the RDK project.