To delete photo(s) from an album, simply select them while browsing the album and hit the "delete" key. You can also right-click a slelection in an album and click "Remove from album" from the popup context menu.
The photo(s) will only be removed from the album being viewed...the originals remain intact.
It's not really unfriendly.
What type of album?
You cannot remove an image from a smart album, the only way to remove an image from a smart album is to make it such that it does not fulfill the criterion for inclusion in the smart album.
In a regular album the delete command tunes into Remove from Album
Because you wrote this
How do I delete a photo from album? There is only link for Delete Version
I suspect you are not in a regular album.
It's not complicated but it does require a bit of thought.
A smart album is an album that is filled automatically based on the filter criterion you set for it. For example I can make a smart album that holds all my 5 start images or all images shot on Dec 11, 2004. The images will automatically be added to and removed from the smart album as the metadata on the image changes. If I re-grade a 5 star image to 4 stars it will be removed from the smart album.
A regular album is populated by you actually adding the images to it. So if you want to make an album of images that have no common metadata then you can;t use a smart album, nothing to filter on, so you just drag the images into the album.
If all you saw in the contextual menu when you right clicked on an image is Delete and not Remove from album, as was in my screen shot, then you were not in a regular album. You were in a project, smart album or folder.
right click on the photo.
The photos I was asking were from regular album, I think.
If the Context Sensitive Menu shows "Delete Version" and does not show "Remove from Album" your currently selected container is not a regular Album.
right click on the photo. BTW, what is smart album and normal album? Is smart album only for smart people? I don't see the reason why it has to be complicated.
Software is fantastically complex.
The User Manual does a good job of introducing Aperture and its parts. Here's the start of the section on Smart Albums: