I have solved my problem, and am sorry I didn’t post my solution sooner if anyone needed it.
I have become somewhat used to the set of warning messages thrown by Encore, and have never had a problem. This time, it said there was an orphaned timeline created when I imported my background for a meny by mistake. I deleted the timeline, not the asset, and everything worked just fine. Interestingly enough, all of the warnings went away as well.
The second possible issue is that, even though there was no warning, I noticed the size of the image file was very near the maximum size. When I deleted the errant timeline, it dropped the size as well. Don’t know if that was the initial problem or not, but, maybe.
Should pay more attention to warnings and their solution in the future.
Joe