On this page the terms attachment, image and media are used interchangably. Strictly speaking, only media attached to a post can be called an attachment.
Post attachments are automatically broadcasted to the child posts upon publishing / updating. Other media may also be copied at the same time.
- Featured images
- Media references in shortcodes in the post
- Media references in custom fields using various add-ons
How media is handled during a Broadcast
Preparations on the parent blog
When the publish button is pressed, Broadcast will:
- Take a note of all media IDs directly attached to the post.
- Note the featured image ID, if any.
- Examine all gallery shortcodes and all media IDs found within are noted.
- Various add-ons will try to find media IDs in various places, for example:
Preparations on the child blog
If the child post already exists, Broadcast will delete all attached media. This is to ensure that all media is kept updated on all child blogs. The deletion can be prevented by using the Protect Child Properties or Update Attachments add-ons.
After the attachments are cleared, Broadcast will try to copy all media.
Copying the media
One after one, all attachments are attempted to be copied to the child blog.
Broadcast will first check to see if a media file with the exact same slug already exists on the blog. If so, the admin setting existing attachments dictates the action to take:
- The existing media can be used.
- The existing media can be deleted and recopied (overwrite).
- The name of the media can be modified slightly when being copied (randomize)
The default is to use the existing media ID.
Using option #2 can result in broken links if other posts reference the same media.
Option #3 will generate very many duplicates.
Each copied media will result in the metadata and thumbnails being regenerated. This usually takes a few seconds per image. To save time and help prevent PHP timeouts, the Duplicate Attachments add-on will directly copy the media without regenerating anything.
Modifying the media IDs
In the case of gallery shortcodes, the contained media IDs are modified to point to the equivalent media on the child post. If you use other shortcodes that contain media IDs, you should have a look at the Shortcode Attachments add-on.
A featured image, which WordPress internalls calls a thumbnail, will automatically be copied whether attached to the post or not.