Filters the post thumbnail size.
Parameters
$size
string|int[]
Requested image size. Can be any registered image size name, or an array of width and height values in pixels (in that order).
$post_id
int
The post ID.
Source
File: wp-includes/post-thumbnail-template.php.
View all references
$size = apply_filters( "post_thumbnail_size", $size, $post->ID );