Thanks @jmone.
Sorry, I wasn't clear in my original post. The information displayed for the particles was retrieved via the "Get Movie and TV Info", and that works as expected so long as the Series Season and Episode are correctly populated.
The image required for the cover of the "STOS S1D2" cannot be retrieved (at least I can't figure it out) via the "Get Movie and TV Info" option because there is nothing "correct" that can be populated for the cover for the boxset. If there is some combination of tag settings for "Get Movie...", that returns these boxset covers, I can't figure it out.
So, only way I seem to be able to get the image needed for the box set is via the "Get Cover Art" option.
Then, after retrieving this cover image it seems to be available to the library, and I see it in JRiver's Cover Art directory, but nothing I do will get it so that the cover art automatically displays in the UI.
If the image is copied to the BDMV directory, the the option "Quick Find in File / Cover Art Directory" adds the cover. It doesn't seem to matter how the image is named, as long as it's an image it will be used for the cover.
But, is it supposed to automatically populate after the retrieval? Kind of seems like it should.