A small python script to wipe out all AMI. Be extremely careful when you run this.

delete_ami.py

import boto3

ec2 = boto3.client('ec2')

images = ec2.describe_images(Owners=['self'])

for image in images['Images']:
    if image['State'] == 'available':
        snapshots = image['BlockDeviceMappings']
        
        print "Deleting %s - %s" % (image['ImageId'], image['Name'])
        ec2.deregister_image(ImageId=image['ImageId'])
        for s in snapshots:
            if 'Ebs' in s:
                if 'SnapshotId' in s['Ebs']:
                    print "Deleting %s" % s['Ebs']['SnapshotId']
                    ec2.delete_snapshot(SnapshotId=s['Ebs']['SnapshotId'])
    else:
        print image['State']