Fargate 1.4 Disk usage

Hey everyone,
I have a service which is running on fargate 1.4. In aws ECR my service image size is around 2.5 GB.
But when I deploy my application to fargate, its disk usage is being shown as 71% which would be 14 GB(1.4 version comes with 20GB space) .
Can some one help me on why and where 14GB is being used.