Why can I not view image attachment pages?

I have a problem with images.

I can see my uploaded images, as previously, through the media library. I can access each image by clicking on “edit”. But if I then click on “View Attachment Page”, I am taken to the “404! We couldn’t find the page!” message. This applies to all images in the library.

At the same, images in some posts (but not all) are behaving differently from before. It used to be possible for readers to click them and see them full size, whereas now that click simply relads the posts in question.

I have experimented with deactivating plugins, but have not found a solution for this. Does anyone know what might cause this, and what might have triggered it?

From what you’ve described, it sounds like the theme doesn’t have an attachment.php template to handling displaying the actual attachment page.

You check on the attachment page, by going to Appearance->Editor, and checking for an attachment.php; however, I believe that answer is incorrect. WordPress should default to displaying the image on the normal blog index page, if I’m not mistaken. Which means the error could have something to do with a custom permalink structure.

Have you changed the permalink structure? If so, try changing it back to default and see if you still get a 404.