What is the difference between base64/ inputstream/ url?

• Base64 returns a base64 encoded text blob in the JSON response that can be decoded into an image/document. This can be a maximum of 5 MB in size.
• If one has large media, then instead one should use a stream, which returns a file stream that can be saved directly. If one has a URL to a media, it can be used to save the media.

What is the difference between sourceID and importCode?

• When importing media via the media import API, one can specify a sourceID for the media upon import. This can also be used later for editing/exporting. This sourceID exists only if set during import and therefore may not always be available.
  
  
• ImportCode is the unique media ID sequence number for media in feed API. Use the Swagger documentation to identify what to use in the different options. ImportCode might have alternative names in the API (mediaCode, mediaId) 
• In feed® GUI the ID sequence number for media is called ID. You can find the media id number in the feed URL when you are looking at a media, or you can activate a column with the ID in feed media to get it in the media list.