Hook after image is uploaded and image sizes generated

Question

I'd like to compress images once they're uploaded to media library. Is there any hook that fires once the image is uploaded and the image sizes generated?

Answer 1

Is there any hook that fires once the image is uploaded and the image sizes generated?

wp_handle_upload fires after the image is uploaded. After the follow-up question, I discovered that images would not be sized at this point.

add_filter( 'wp_handle_upload' 'wpse_256351_upload', 10, 2 );
function wpse_256351_upload( $upload, $context ) {
  //* Do something interesting
  return $upload;
}

Added:

Images are resized on line 135 of image.php. There are no hooks in method to resize the images.

At the end of the wp_generate_attachment_metadata() function, wp_generate_attachment_metadata fires. This is after the image sizes are generated.

wp_read_image_metadata is another option. It fires before wp_generate_attachment_metadata but after image sizes are generated.

Answer 2

Use the wp_generate_attachment_metadata filter for this, it's fired in the wp_generate_attachment_metadata function.