Before making any changes to your site, make sure you have a recent (daily) backup copy from your hosting company that you can restore from in case anything breaks.
You can change the thumbnail size for the Cook'd Pro recipe index by adding this to the code snippets plugin:
add_filter( 'genesis_pre_get_option_image_size', 'mycustom_cookd_change_recipe_index_image_size', 12 );
function mycustom_cookd_change_recipe_index_image_size() {
return 'cookd-vertical';
}
Gist: https://gist.github.com/feastdesignco/b62bb6c30a29711de19504669507411a
This works by overriding the theme's specified image size (cookd-grid) with the value being returned (cookd-vertical) at a filter with a later priority (12, instead of 10).
Replace 'cookd-vertical' with the slug of the other image size you want to use. For reference, these are the built in sizes for Cook'd Pro:
add_image_size( 'cookd-large', 1170, 617, true );
add_image_size( 'cookd-medium', 768, 405, true );
add_image_size( 'cookd-small', 320, 169, true );
add_image_size( 'cookd-grid', 580, 460, true );
add_image_size( 'cookd-gridlarge', 1170, 800, true );
add_image_size( 'cookd-vertical', 1000, 1477, true );
You may then need to install and run the Regenerate Thumbnails plugin to get your images re-cropped to the new size.
Please make sure you have a backup of your files to fall back on and that you know how to restore your site via FTP or your hosting cpanel in the event of a coding error.