10up ran some great testing sessions where one particular hurdle was highlighted — users don't immediately pick up on the "pencil" icon as the way to edit or swap the image. More info at https://10up.com/blog/2018/testing-the-gutenberg-publishing-userflow/
This has come up anecdotally before as well.

One possibility is to use a text button instead:

Another could be to place the edit button within the image (on selection).
It'd also be nice to support "drag to swap" on the image block. This has also come up before.
10up ran some great testing sessions where one particular hurdle was highlighted — users don't immediately pick up on the "pencil" icon as the way to edit or swap the image. More info at https://10up.com/blog/2018/testing-the-gutenberg-publishing-userflow/
This has come up anecdotally before as well.
One possibility is to use a text button instead:
Another could be to place the edit button within the image (on selection).
It'd also be nice to support "drag to swap" on the image block. This has also come up before.