You can pull the image and push it to AWS ECR.
You need to create the repo in AWS first.

# Tag your image so you can push the image to this repository
docker tag <image_name>:latest <account_id>.dkr.ecr.<region>.amazonaws.com/<repo_name>:latest
# Push this image to your AWS repository
docker push <account_id>.dkr.ecr.<region>.amazonaws.com/<repo_name>:latest
Yes, you can use any image as base image. You can use the image you push to AWS ECR too, at the top of your Dockerfile
add below code:
FROM <account_id>.dkr.ecr.<region>.amazonaws.com/<repo_name>:<image_tag>