Statuses/update does not tweet with image


I have a reddit->twitter bot, which works great. It uses the deprecated update_with_media, so I decided to update it to use the new media/upload -> statuses/update system. I managed to get the media/upload working, it gives me an id (e.g. 557429622128648192), but when I tweet using media_ids as an argument in my POST, there is no image attached.

media/upload output:

'{"media_id":557423095707750402,"media_id_string":"557423095707750402","size":832848,"image":{"w":1500,"h":1125,"image_type":"image\\/jpeg"}}' }


Thank you!