Images

Image data is returned if a request successfully completes, and if the request either does not include a req= command, or if req= has one of the following values: img, debug

The HTTP response MIME type is determined by fmt=, or, if fmt= is not specified, it depends on the value of attribute::Format.

The HTTP response status is ‘200 OK’ if the request method was an unconditional GET or HEAD.

The server may reply with status ‘304’ (not modified) and not return any image data in response to a conditional GET request (with the If-Modified-Since field present in the request-header).