Resolver Images do not show up in WorldCat.org or WorldCat Discover by design.
In the OCLC Service Configuration site, in OpenURL Resolvers, and then Manager Resolvers, there is a field where you can enter your Resolver Image Location. That image can function like a button and send users to your institution's request page with the appropriate information loaded. WorldCat.org and WorldCat Discovery do not utilize this function.