The latest version of macOS, Catalina, has a lot of quirks (to put it nicely). One crops up in Photos when you’re working with manually created albums—those are albums into which you choose which images and videos appear, as opposed to smart albums, which rely on search criteria.
In Mojave and earlier versions of macOS, you could select one or more images in the album and either right-click to Delete X Images or use the menu item Image > Delete X Images. When confirmed, that would remove the images from your Photos library, as opposed to Image > Remove X Photos from Album, which removed the media from being part of the album being viewed, but left the photo or movie in your main library.

Apple changed Photos deletion options between Mojave (left) and Catalina (right).
I can only guess this menu item was removed to avoid accidental deletion. Perhaps users misunderstood the difference between Delete and Remove all the time, and Apple viewed this as a user-experience improvement?
You can restore Delete, however: just hold down the Command key and it replaces the Remove option while the key is held down. You can tap Command with the menu selected and see it toggle between the two states. You can also press Command-Delete to remove images without any confirmation. (“Deleted” images are actually moved to the Recently Deleted special album, where you have about 30 days to revert your action.)
You may not want to select images one at a time or in small groups to delete, however, as you might be concerned that you would get rid of the wrong thing. Here are two strategies that work in Photos in macOS all the way through Catalina that can help you assemble a list of images to delete from your library while maintaining more control.
Mark images as favorites and make a smart album
As your first pass in an album, mark images you want to delete as favorites. Or, inversely, mark images you want to retain by favoriting only the ones you want to keep. Choose whichever approach makes more sense to you.
Then, create a smart album:
Choose File > New Smart Album.
Set the first criterion as Photo, is, favorite if you’ve marked images to delete as favorites; choose “is not” if you favorited images you want to retain and this select only unfavorited images.
Click the + (plus) sign at the far right.
Set the second criterion as Album, is, album name.
Name the smart album something descriptive, like “Images to delete from Berkshires album,” and click OK.
Select the smart album in the left-hand Photos sidebar.
Choose Edit > Select All and then Image > Delete X Photos and confirm your deletion.

Create a smart album that collects items tagged for deletion
Using the favorites tag doesn’t work in cases in which you already mark photos with a heart for another purpose. In that case, try the following alternative.
Add a keyword and search on it or make a smart album

Tag images for deletion using a keyword in the Info palette.
You can use a unique keyword and either a Photos search or a smart album to match results. For instance, pick deletethis
as your deletion keyword while following these steps:
Choose Window > Info.
Select one image at a time or groups of images and then type your deletion keyword, such as
deletethis
, into the Keyword filed in the Info palette.Type comma or press tab to add the keyword.
Repeat steps 2 to 3 as necessary.
If you want to use the search options:
Type
deletethis
into the Search field of the Photos window.In results, click the entry under Keywords.
Choose Edit > Select All and then Image > Delete X Photos and confirm your deletion.
If you want to use a smart album:
Choose File > New Smart Album.
Set the first criterion as Keyword, is,
deletethis
.Name the album something descriptive, like “Images to delete from Berkshires album,” and click OK.
Select the smart album in the left-hand Photos sidebar.
Choose Edit > Select All and then Image > Delete X Photos and confirm your deletion.
This Mac 911 article is in response to a question submitted by Macworld reader Susan.
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