When you get sent a webmention and it contains a h-card/
u-photo, IndieBlocks will attempt to download the image and store it locally.
By default, avatars are stored in
If, later on, IndieBlocks encounters an image with the same URL and the local copy is over a month old, it will re-download and overwrite the previously stored avatar. Newer images are not updated.
If a local avatar is ever deleted, it will be “replaced,” on your site’s front end, by either your WordPress’ default avatar or the “mystery man” image.