CircleCI docker image pull policy

Say we have a simple .circleci/config.yml file:

version: 2
jobs:
  build:
    docker:
      - image: account-id.dkr.ecr.us-east-1.amazonaws.com/org/repo:0.1

will circleci always attempt to pull the latest image, or do we need to set an image pull policy of “always”?

something like:

  build:
    docker:
      - image: account-id.dkr.ecr.us-east-1.amazonaws.com/org/repo:0.1
        imagePullPolicy: Always  

?

Source: StackOverflow