Featured Image Size

Alright, this is a old thread. But anyway.
The title doesn’t say so much.

You wonder what’s the default dimensions for featured images?

If your open the functions.php file, you will find the lines that say:

// This theme uses post thumbnails
  add_theme_support( 'post-thumbnails' );
  set_post_thumbnail_size( 668, 9999 ); // Unlimited height, soft crop

  // Register custom image size for image post formats.
  add_image_size( 'sempress-image-post', 668, 1288 );

The numbers are in pixels (max size).