Today I posted my update to ctshryock/MGTwitterEngine which allows you to use the API's update_profile_image and update_profile_background_image. I added to the demo app a window that lets you select an image for either profile image or background image to see it in action.
I had to modify some of the internals to get this to work... originally the _sendRequestWithMethod:path:queryParameters:body:requestType:responseType: method built the NSMutableRequest object internally, but to minimize code duplication I split the initial creation of the request into a new method _baseRequestWithMethod:path:queryParameters: to do that, and added a new method _sendDataRequestWithMethod:path:queryParameters:filePath:body:requestType:responseType: . Both _sendRequest... and _sendDataRequest... call _baseRequest... to start, with the latter adding the needed form/multipart data to the request.
