I have all of my album art saved to a single folder and I'm using the following format in Preferences > Display.
..\..\..\Artwork\Albums\%album artist% - %album%.*
..\..\..\Artwork\Albums\Soundtrack - %album%.*
..\..\..\Artwork\Albums\Various Artist - %album%.*
..\..\..\Artwork\Albums\$ascii($replace(%album artist% - %album%,\,,/,,:, ,|,,*,,",,<,,>,,?,)).*
..\..\..\Artwork\Albums\Soundtrack - $ascii($replace(%album%,\,,/,,:,,|,,*,,",,<,,>,,?,)).*
..\..\..\Artwork\Albums\Various Artists - $ascii($replace(%album%,\,,/,,:,,|,,*,,",,<,,>,,?,)).*
The strange part is that some files display and others do not. I think it might be that the issue is related to illegal characters but since I can't "see" the search pattern F2K is using, I'm not sure what to use for a corresponding search preference. Do I need to escape these characters when I use replace?
I haven't embedded the album art in these files so that isn't causing some of them to be displayed.