Django-multiuploader: failed to upload pcd format

Question

I am new to django, and I using the django-multiuploader 0.2.40 for my project.

what I want is to upload .pcd file-format(PCL-lib), but when I using this plugin-app, I will get [IOError: cannot identify image file]

so I added some description to the "MULTIUPLOADER_FORMS_SETTINGS"

like:

'default': {

      'FILE_TYPES': ['pcd', 'jpg', 'jpeg', ...],
      'CONTENT_TYPES': [
              'text/pcd',
              'image/jpeg',
              'image/png',
              ...        
      ],    

},

'images': {

     'FILE_TYPES': ['pcd', 'jpg', ...],
     'CONTENT_TYPES': [
         'image/pcd',
         'image/gif',
         ...
     ],

and this make nothing different, still get ioerror.

but the stranges is .pcd file still can successfully save to my database.

something I did is wrong?