How to set images sizes
// Thumbnail sizes
add_image_size( 'wpbs-featured', 780, 300, true );
add_image_size( 'wpbs-featured-square', 600, 600 );
add_image_size( 'wpbs-featured-news', 600, 300, true );
add_image_size( 'wpbs-featured-home', 970, 311, true);
add_image_size( 'wpbs-featured-carousel', 970, 400, true);