I'm sure I'm missing something, but I don't see how to delete a photo. Preferably, I'd like to delete the photo from the library and thumbnails at the same time. Is there a way to do this?
Select the image(s) (in Library module) and hit the Del key to remove from Library but leave image on disk. Hit Cmd+Del to remove the image to trash. You can also use the Context menu in Library module.