As far as I know that feature is not available.
Myself, I have used the old 'Cut and Paste' technique.
However, if you open the sidebar you can drag images from the album you are viewing to another album. However I have noticed that it 'Copies' the images rather than 'Moving' them.
Hopefully in a future update Apple will put back this feature, I've seen a lot of discussion regarding this issue on the Apple forums.
The feature is not missing. There are three ways to do this:
1) Select the images you want to add to an album, then click the + icon in the upper right. You'll then have the option to select the "target" album, or create a new album.
2) Expose the Sidebar (View > Sidebar) and drag and drop the desired images to the desired album
3) As always, if you want to create a new album, you can select the images you want to add to that album and then choose File > New Album...
Dragging images from one
album into another (or selecting them when creating a new album) has
always "copied" them (the assumption being that you want to add the same photo to other albums, not that you want to move them from one album to another). There's one master image, and that image can appear in any number of albums. Actual copies are not made - it's the equivalent of linking a photo on a web page. There is a separate Remove From Album function.
You're confusing Events and Albums. Yes, dragging an image from one
Event to another Event would move it, rather than copy it. However, dragging from an Event to an Album would "copy."
Events do not exist in Photos. Years/Collections/Moments is roughly equivalent (organizing by the date the images were taken), but images cannot be moved from one Year/Collection/Moment to another.
"Copying" images by dragging and dropping is how I normally work - I have one album containing an entire shoot, I have another containing select images from that shoot, I have various "greatest shots" albums... So, I'll drag an image from the shoot album to the select images album, I'll go through the select images albums for candidates for the greatest shots albums... just dragging and dropping as I go, and nothing is removed from any of the other albums (which is just the way I want it).
Photos, just like every app, comes with a very useful Help function. It would be helpful if folks made better use of that resource.
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I'm not a happy bunny. I now have no way of tracking the photos I have copied over and those I have not... Total mess.
Copied from where, to where? What method had you used in the past?