How to restrict wp generate attachment metadata() to certain intermediate image sizes

Question

In Wordpress, we have added our own intermediate image sizes to the standard Wordpress sizes using add_image_size().

Using our own admin interface to upload images, we then use wp_generate_attachment_metadata() to create all thumbnails and save them to a predefined folder on the server.

However, we would like to restrict wp_generate_attachment_metadata() to generate our custom defined image sizes ONLY and ignore the Wordpress standard sizes.

Is this possible?

Thanks in advance for any help!

Answer 1

wp_generate_attachment_metadata() uses get_intermediate_image_sizes() to get the sizes to work on, which makes them filterable via intermediate_image_sizes.

Additionally, you can filter them after cleanup with intermediate_image_sizes_advanced, the result should be the same.