Ok, I renamed the file and now it works.
I think it has something to do with filename handling. The filaname, in hex, is "e280 af50 4d2e 706e 67", which appears as " PM.png" (a space-like-character, then "P", then "M", then ".png").
This shows up in Decker's file picker as the following -- note the "?" in the filename.