It seems like an very simple question, but yet I could not find the answer. When I make an instance on Amazon AWS and then make some changes and create an AMI where is that AMI stored? S3? Will making extra AMIs be added to the amount payed each month?
AMIs and snapshots are stored on S3 in the standard storage class. You cannot access this area of S3 directly, only via the service web interface or APIs. You pay S3 standard rates for this storage.
There's no easy way to tell how much storage these "hidden" sections of S3 take up. The best way I've found is on the monthly bill.
References (good as at December 2016)
You can back up the data on your EBS volumes to Amazon S3 by taking point-in-time snapshots.
Amazon EBS-backed AMIs launch faster than Amazon EC2 instance store-backed AMIs. When you launch an Amazon EC2 instance store-backed AMI, all the parts have to be retrieved from Amazon S3 before the instance is available. With an Amazon EBS-backed AMI, only the parts required to boot the instance need to be retrieved from the snapshot before the instance is available.
Snapshots occur asynchronously; the point-in-time snapshot is created immediately, but the status of the snapshot is pending until the snapshot is complete (when all of the modified blocks have been transferred to Amazon S3)
Your AMI is stored as an EBS snapshot in the same region as the instance. You will pay for the cost of that EBS storage.
in order to access your AMI's after you created and image of it, it is created and stored in your AMI'S you will find this when you are launching a new instance to the left side of your page , you can see options like community AMI, market place..etc. over there you must find a column "MY AMI's" and there you will find your AMI which you created.
Usually AMI's that we create would store in a single region where you have created.
If you want to launch instances with that AMI, you can use "COPY" to the specified region.