If you are importing your images after running them through Rawsie and in Select no thumbnails are showing as the example below, it's highly likely due to the embedded previews are quite small.
How to resolve:
You can import your images into Select and then compressing them through Rawsie once your selection is complete.
If you want to run them through Rawsie before importing into Select, make sure to have this option ticked when converting the files. After doing this, your imported images should now load.