API Upload returning only image, rather than JSON/XML

I'm using Python to upload url images, instead of the site, since you have to enter each url one at a time now and instead of  the expected JSON/XML response, I've been getting the entire image back. It's been awhile since I've used the API, but I don't think I'm doing anything wrong:

api url is: "http://api.imgur.com/2/upload.json"

adding api_key, image and type as parameter to my POST request.

Here's the code, minus a filename and API key http://pastebin.com/X1vYNdvw