匿名上传File对象到Imgur API（JSON）给出了身份验证错误401

I've created a class UploadToImgurTask as an AsyncTask that takes a single file path parameter, creates and sets an MultiPartEntity, and then uses Apache HttpClient to upload the image with said entity. The JSON response from Imgur is saved in a JSONObject, the contents of which I display in LogCat for my own understanding. as an As