If you use Preview to quickly review multiple photos, you can easily delete unwanted images within the current view.

• Open a few photos simultaneously with Preview.
• From the Thumbnails Sidebar, select the image(s) you don’t want
• Use the “Move To Trash” keyboard shortcut (just like in the Finder): Command – Delete.

The unwanted item will disappear from Preview and be moved from the Finder into the trash.

Alternatively, you can Right-click, or Control-click on the image and select Move To Trash from the pulldown menu.