Update a image on your account with the specified parameters. Don't forget to specify PUT as the request method as GET will call the show action rather than update.
https://www.streamio.com/api/v1/images/image_id.format
PUT
204
Just remember to PUT and you'll be fine.
curl -u username:password \
-X PUT \
-d "title=My Sweet Lolcat&tags=cute,and,awesome" \
https://www.streamio.com/api/v1/images/4c483ea1bf4b9802c5000029.json