Testing this out with AWS

PreventMarketplaceImages.json

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "VisualEditor0",
            "Effect": "Deny",
            "Action": "ec2:RunInstances",
            "Resource": "arn:aws:ec2:*::image/ami-*",
            "Condition": {
                "StringNotEquals": {
                    "ec2:Owner": [
                        "123456789012",
                        "${aws:PrincipalAccount}"
                    ]
                }
            }
        }
    ]
}