Main post image different sizes

    // Thumbnail sizes

    add_image_size( 'thumb-small', 80, 80, true );//used for Hueman Dynamic Tabs widget <= april 2020 changed from 160x160 to 80x80 for https://github.com/presscustomizr/hueman/issues/866
    add_image_size( 'thumb-standard', 320, 320, true );//used for standard post list / and for related posts
    add_image_size( 'thumb-medium', 520, 245, true );//used for classic post grid / and for related posts
    add_image_size( 'thumb-large', 720, 340, true );// used in singular to display the featured image ( when cropped option checked ) / used in image and audio post formats
    add_image_size( 'thumb-xlarge', 980, 450, true );// used in featured content on blog page
    add_image_size( 'thumb-xxlarge', 1320, 500, true );// used in featured content on blog page

There are 6 images versions in wp-content/themes/hueman/functions/init-after-setup-theme.php.
And if you have change your theme for this one, you’ll have to use the Regenarate thumbnails plugin