Amazon S3 + CloudFront CDN AccessDenied after changing URL to test

CloudFront isn't working for me? Maybe I'm missing a step...

I created a new distribution, and chose an Origin Domain Name from a drop down from Amazon S3 Buckets that I'm using for my application. bucketname.s3.amazonaws.com

Left everything else default... and then when I tried to change an image URL, I get an XML error with AccessDenied.

I did:

http://ift.tt/1Jwj5li

http://ift.tt/1KAGikY