Using Custom policy to restrict OS

[NajdDer]

Hell all 

I am trying to find a way to restrict my users in my org from deploying and using certain OS in the vms, so for example I dont want them to use Fedora . So I thought of Custom policy to do that and I deployed this code in my terraform 

gceimgblkuwos:
    display_name: "Custom OS: Block all unsupported OS for VMs"
    description: "Block all unsupoprted OS"
    action_type: "DENY"
    method_types: ["CREATE"]
    resource_types: ["compute.googleapis.com/Image"]
    condition: "resource.family.contains('Fedora')"
    projects:
    - target: najdplayground-01-1304
    enforce: TRUE

Its not working , I get an error so I guess I used the wrong resource Type/Condition

any clue? 

Regards
Najd