Yeah, that isn't really a bug. As of now, I couldn't figure out how e.g. the scene browser shows the .json file names but replaces the generic grey sheet with the .jpg if one exists. If I make the plugin search for .si files i always get the grey sheet, regarless if there is a .jpg present. So I decided to only display (and search) for .jpg files, which unfortunately means no .jpg = nothing is found.
I would gladly have the best of both worlds, so if you know how to replicate the behaviour of the scene browser let me know!
All I could do for now is to show all file types, but then the .jpg and the .si would both be visible, which is not what i want. I'll look into it once again, but this is not on top of my priority list. More options for customization, more morphs/regions and male support are far more valuable, do you agree?