The culling process can be tedious. But selecting the keepers from hundreds or even thousands of photos from a shoot is an essential step. The most obvious tool Lightroom provides to help is the Picks tool, where you can flag an image simply by pressing P. But there's also a corresponding Rejects tools, where you can reject an image (or images) simply by pressing X.
How you use that depends entirely on your own workflow preferences. Maybe you use it as a first pass to filter out files that are unusable, such as ones that out of focus or the subjects eyes are shut. So you might end up with keepers, maybes, and rejects. Or maybe instead of choosing picks you're using the reject tool for everything that's not a keeper.
But rejecting an image isn't the same as the deleting it. Sure, the thumbnail does get grayed out to make them visually separate, but they remain in the catalog and on your hard drive. That's a very handy safety precaution so that you can review and undo if need be.
But what if you want to delete the rejected images? Sure, you can select them individual and delete them. You can also use the filters to isolate just the rejects and delete those.
But there's a quicker way, using the built-in 'delete rejected files' function. There are two ways to do it:
- Use keyboard shortcut CMD+DELETE (Mac) or CTRL+BACKSPACE (Windows).
- Use menu: Photo > Delete Rejected Files
When you do that, you'll get the option to delete the files from your hard drive or simply remove them from the Lightroom catalog (in which case the files stay on your hard drive but won't be visible in Lightroom).