Imagery versus working memory
Researchers treat visual imagery (conjuring a picture on demand) and visual working memory (holding and manipulating something that's actually in front of you) as separate systems. Aphantasia usually involves the first one. Some studies suggest the second can remain intact, or even compensate, in people with aphantasia, with accuracy kept but a different strategy used. In practice, many people with aphantasia find editing, collage or live production easier than producing an image from scratch. The research is still developing, so treat it as a useful lead and not a guarantee.