Just ran into an oddball. If my project contains a PDF without a representing image, trying to add a "date view" produces a "red X" thumbnail, and making the album produces an error message like this:
java.io.IOException: AlbumObject /By date/2025/Oct can't be represented as an image
at se.datadosen.jalbum.AlbumImage.<init>(AlbumImage.java:51)
at se.datadosen.jalbum.ThemeImageProcessor.processThemeImage(ThemeImageProcessor.java:93)
at se.datadosen.jalbum.AlbumBean.makeAlbumForFolder(AlbumBean.java:2148)
at se.datadosen.jalbum.AlbumBean.makeAlbumForFolder(AlbumBean.java:2167)
at se.datadosen.jalbum.AlbumBean.makeAlbumForFolder(AlbumBean.java:2167)
at se.datadosen.jalbum.AlbumBean.makeAlbum(AlbumBean.java:3791)
at se.datadosen.jalbum.AlbumBean.smartMakeAlbum(AlbumBean.java:3627)
at se.datadosen.jalbum.JAlbumFrame$7.run(JAlbumFrame.java:1210)
Same problem with an "alphabetic view." I can sense the underlying problem - objects with only an icon aren't being handled properly in views. They should, of course, be grabbing the generic icon for a PDF, for example.