To update the region maps execute the following lines in your terminal:
$ regions=$(aws ec2 describe-regions --query "Regions[].RegionName" --output text)
$ for region in $regions; do ami=$(aws --region $region ec2 describe-images --filters "Name=name,Values=amzn-ami-hvm-2017.03.1.20170812-x86_64-gp2" --query "Images[0].ImageId" --output "text"); printf "'$region':\n AMI: '$ami'\n"; done
$ for region in $regions; do ami=$(aws --region $region ec2 describe-images --filters "Name=name,Values=ubuntu/images/hvm-ssd/ubuntu-xenial-16.04-amd64-server-20170721" --query "Images[0].ImageId" --output "text"); printf "'$region':\n AMI: '$ami'\n"; done