Deletion seems so final, and it’s worthwhile to pause a moment and reflect before clicking any Delete button or selecting any Delete menu item. In Photos for macOS, you’re presented with many opportunities to delete items and collections, but Apple, fortunately, spells out the effects.
organizing structures it makes available. When you delete any album you’ve created, whether it’s smart or static, Photos only deletes the organizing framework. The original media remains in the library untouched. Apple even makes an effort to reassure you. When you Control-click (or right-click on a two-button mouse) any album in the My Albums list in the sidebar and choose Delete Album or Delete Smart Album, Photos brings up a prompt that explicitly tells you what’s going to happen. The wording is a little quirky, saying that “items in this album will still be visible in your photo library,” but I assume Apple decided on that language to be clearest to the least-sophisticated users, who don’t necessarily understand file management and storage. You can delete albums with great aplomb without worrying about the original media being deleted when you do. If you actually want to delete an image or video:
>In the main Photos view, select the image or video and choose Image → Delete Photo/Delete Video or press the Delete key on your keyboard.
>In other views, those options aren’t available. Instead, right-click an image or video in any view and choose the Delete option. If you have iCloud Photos enabled, Photos warns you that a deleted image or video will be removed permanently from every linked device’s Photos library, too. (Deleted images are held for 30 to 40 days in the Recently Deleted folder.)