How to fix images to the container size

@khanpkkhan

so on this page:
https://themesflag.com/category/wordpress-business-themes-free/
all your thumbnails are square

and

you want them to be the size on the post page:
https://themesflag.com/moesia-free-parallax-wordpress-theme/
assume these are identical sized screenshots

if so, the below should help:

https://codex.www.ads-software.com/Settings_Media_Screen

https://codex.www.ads-software.com/Post_Thumbnails

you may need to check the part referring to functions.php where you may need to do some work