I have tried:
1. placing the bitmap image in the package with the java classes
2. grabbing that image via InputStream
3. Casting the inputStream to an Object
4. using the IPIctureMarkerSymbol.equals(Object object) method.
The program does not fail or produce an error, but the image does NOT display with this attempt.
Again the image DOES display with the file path as String, but that is not a sustainable plan for deploying the add-in.