Filter the default Twitter card image, used when no image can be found in a post.
Parameters
- $str
string Default image URL.
Changelog
- Introduced in Jetpack 5.9.0
How to use this hook
Notes
Alternatively, you can also rely on thejetpack_images_get_images filter to define a fallback image that will be used in multiple areas of Jetpack (Open Graph Meta tags, Twitter Meta tags, Related Posts, and more).
Jetpack Developer Resources 