Hello and thanks for the comments.
Looking at your screenshot, I can guess that you use a big character sheet set like default (4 big monsters on the sheet, one per line, all facing down), isn't it?
The plugin expect a 4 direction sheet. For big character sheets, that means a single monster per sheet facing the 4 directions.
If you don't use 4 directions for your big monsters, then simply copy paste the same big monsters on the 4 lines of the sheet.
EDIT: I think you could also use the comment tag <fix mirror image> so it will reflect the image as is...
Regards.
