iPhone Photos app: Delete button not working for "From My Mac"

You say "duplicates." Are you meaning those offending pictures with no delete button?

It's been a really long time since I've actually done this, and I use a Mac, but I'll try:

Do you have a computer with iTunes? See this:

Sync photos in iTunes on PC with devices - Apple Support

The idea is to sync, but set the checkmark to sync photos, but do not select any albums.

Pictures that are transferred through a cable from a computer, perhaps with iTunes, can be shown by Photos, but they're not "owned" by Photos. So these pictures can't be edited or deleted by Photos, and they can't be synchronized with iCloud Photos. The idea is that the originals are kept on the computer, and they are transferred to the phone temporarily. So one way to delete them is to use the computer to transfer an empty set of "pictures" to the phone, and the empty set will replace the others. In using iTunes for this, it may give the option to deselect the pictures that are already there. On a Mac we might do it with the app Image Capture in the Applications folder, but that's just with a Mac.

Another way to get rid of all the non-deletable pictures is to momentarily turn on iCloud Photos. You get a scary warning that these will be deleted. When you say OK, then they're trashed, and then Photos will start to transfer the other pictures to iCloud.But you can turn off iCloud and stop the sync before it happens.

If you want to save some of these non-deletable pictures, then you can use "Share" to save them to Files. Then re-import them from Files to create fully useable versions.

On aMac with macOS 10.15 or later, there is no longer iTunes, but the manual syncing is done with the Finder. I have not done this in a long time, because using iCloud Photos so much easier.

Have a look at this document: https://support.apple.com/en-us/102375

Use the setting "Sync: Selected albums" and do select only the albums with the photos you want on your iPhone or none at all. The new sync will replace the previously synced photos, as Richard explained.

SabDuman wrote: … (you call it: "they're not owned by photos" - which means not owned by me),

No-- it means those pictures are not under the control of that app, just as a Word document isn't controlled by an Excel app-- you may be able to see it in the wrong app, but you don't have the same control. The reason Photos is limited is that those pictures are temporary, and your control over them is through the computer you're using to store them.

When a company refuses millions of requests from its customers to consider adding a simple delete button, it's no surprise that the struggles of its customers matter the least.

This really isn't a site for complaints. We try to help people with technical problems.

It's important to understand that Photos is not a file management system like Explorer or Finder, so people sometimes mix up the behaviors of these apps. Pictures in Photos are not files, but rather they consist of information in a database. This has extraordinary advantages, but it may require a bit getting used to. Using iTunes type methods to transfer pictures by cable moves the picture file, but it leaves behind lots of information that's in the database. With iCloud, we can synchronize the entire Library of information.

This article is very basic, and it's made for Macs, but it some of it may be useful to you:

Basic Terms about Photos