Hey Robert,
it is definitely possible but it will require you to write some code. You will need to implement the OnContextChange() method and change your picture on-the-fly based on the currently selected field.
There are two types of picture controls - one bound to a binary data stored in the form and one bound to an external link. Doing what you want is much easier with an external link, you just need to maintain a list of image links and set it accordingly depending on what the currently selected field is.
Unfortunately, I cannot provide a code example at this time, maybe somebody else would :)
Good luck,
Dave
David Airapetyan / Software Services ArchitectQdabra® Software / Streamline data gathering to turn process into knowledge