I assume the whole point of the "secret code image" is to prevent automated code from seeing it, so I doubt WinRunner will be able to do so.
You need to think "what would I do if I couldn't see that code myself"?
One way - set up your test system so that it always uses the same dummy secret code (for example "test"). Then you could just hard-code "test" into your script.
Another way - find some other way to query the system to get the "secret code". Perhaps a SQL query could do it? Obviously the system uder test can validate the secret code, so it may be stored somewhere.
Another way - have a switch in your test system that could display the secret code in a place that your script can read. Perhaps a field that exists only when the system is run in test?