What is the cost of container image storage?

You can see your actual daily costs by going to the console and choosing cost management service and selecting cost explorer and then choosing current month and daily in the drop downs and group by usage type to view the costs being charged per use type. You would be able to understand the breakdown of different services costs here.

Lifecycle Policies in ECR will allow you to make rules that automatically expire your older images and reduce storage costs. For example, this policy will expire any images that are older than 14 days.

The storage pricing for ECR is $0.10 per GB / month for data stored in private or public repositories. Continuing to add images to your repository without cleaning old images up will increase your storage costs. There is also a cost for data transferred out of the repository.

Usually when you are building and pushing an image multiple times a day only the top layer changes. If the intermediate layers are not changed the storage is not duplicated in ECR. When pushing an image you may see a 'Layer already exists' message which indicates the repository is reusing storage for a layer since it has not changed.