The guidance offered here in troubleshooting the problem helped greatly - thank you to everyone. I tested contents of an exported JAR; I used diagnostic code suggested by Kishan to determine if my code could "see" the image. I believe it might have something to do with the way Eclipse works/refreshes if I move images around in the file system instead of the Eclipse import function. Finally, in order to get it to work, I made the following changes: I created a new project and two sub-packages - one for 'resources' and one for my code class. Then I right-clicked > import on the resources package in Eclipse to get the image.
The only thing to change in my code is ....getResourceAsStream("/resources/strawberry.jpg");