Thanks for the feedback (both of you!) - when writing this, I envisioned a use case where the secret was static within the application, so it is easy enough for the developer to check their secret is 32 characters and not have to bother with checking that particular error. I didn't use panic because although a non 32 character secret puts my library in an unrecoverable state, it doesn't mean the application implementing the library is also in an unrecoverable state, hence why it returns an error instead of panicing.
Also, in terms of the top comment in this chain, the work server (master) never gets work from the workers, the workers push completed work back to the server, maybe this isn't clear within the current docs. All communication between the worker and server has to be coordinated by the application implementing the library.
This solution (and those listed in the comments) are all very interesting solutions, well done. They might not work with different colour images, but they are interesting nonetheless.
Thats a nice story, but unfortunately not the truth. This was simply a spur of the moment idea and I wanted to see if it worked, which to a relative degree it did, hence why I posted it. The main goal of posting it is to show how easy it would be for a website to show ads to a user, even with an extension such as Adblock enabled. In regards to the account, I haven't had a need for a HN account before now.
Correct, it isn't supposed to be used with ad providers that Adblock may (or may not) already block, it's supposed to work with internal ads that would come from the same domain as the content providers.