Return the URL of the next adjacent image in a gallery

[iandstewart]

A function that returned the URL of the next adjacent image for an attachment in a gallery post, or the URL of the parent post if there isn't an adjacent image, would be a really useful enhancement for attachment templates.

Attached is a diff of media.php with the custom function I rolled from adjacent_image_link() to do just that.

[westi]

Sounds like an interesting idea.

Does this not need to be aware of the ordering of the gallery though?

[iandstewart]

That is … true. It works just like adjacent_image_link() and will only return the next adjacent attachment URL—completely ignoring the gallery ordering.

[scribu]

What about get_previous_image_url() ?

[ericlewis]

This isn't possible since 3.5; galleries are no more synonymous with the attachments uploaded/related to the post, and multiple galleries can exist in a post's content utilizing the the ids attribute on the [gallery] shortcode. Closing this out as wontfix.

[SergeyBiryukov]

adjacent_image_link() is filterable since [23140], see #22829.