I can upload images and gif without any problems.
This is a response:
HttpResponseProxy{HTTP/1.1 400 Bad Request [cache-control: no-cache, no-store, must-revalidate, pre-check=0, post-check=0, content-disposition: attachment; filename=json.json, content-type: application/json;charset=utf-8, date: Tue, 07 Feb 2017 18:47:19 GMT, expires: Tue, 31 Mar 1981 05:00:00 GMT, last-modified: Tue, 07 Feb 2017 18:47:19 GMT, pragma: no-cache, server: tsa_d, status: 400 Bad Request, strict-transport-security: max-age=631138519, vary: Origin, x-access-level: read-write-directmessages, x-connection-hash: 494626923301bf57bd4d6e0c82b2cc56, x-frame-options: SAMEORIGIN, x-rate-limit-limit: 415, x-rate-limit-remaining: 412, x-rate-limit-reset: 1486496058, x-response-time: 339, x-transaction: 005055d400ba2c97, x-tsa-request-body-time: 4525, x-twitter-response-tags: BouncerCompliant, x-xss-protection: 1; mode=block] org.apache.http.client.entity.DecompressingEntity@7e1fa8a4}
This is my video:
https://drive.google.com/file/d/0B5BtJsJAFnUbZVhYenYxRkp3ZEE/view?usp=sharing