Preventing Image Attachment Pages Activating

For some reason, I’m getting traffic to image attachment pages rather than image files.

Here’s a gallery on my site:

https://www.workingauthor.com/wp-content/uploads/pirates-of-the-caribbean-2011-bus-shelter-posters-4.jpg

When you click a thumbnail it links to the image file which is what I want. However, attachment pages are still available and somehow people are discovering them:

https://www.workingauthor.com/pirates-of-the-caribbean-on-stranger-tides-2011-posters/pirates-of-the-caribbean-2011-bus-shelter-posters-4

Is there a way to deactivate image attachment pages altogether so that traffic goes to a 404 instead?

Thanks in advance for the help.

V