When I it the delete button, the picture disappears from the library (without warning - confirm deletion...) but then it still is on my hard drive, taking up space! How do I get rid of the images I don't want after a shoot?
On the Mac version, select the file(s) you want to delete and then either use Control-Click>Remove and Trash elected Photos or go to the Library Menu and choose Remove and Trash Selected Photos (see screenshot below). Lightroom will ask for confirmation before moving the selected files. You'll still have to empty the trash to regain space. I guess it's the same on Windows.