Hi @atta-ur-rehman
I hope you’re well today!
I’m not sure what do you mean by “main image” but I’m assuming it’s the original full-size image.
If that’s the case, then you just need to go to “Smush -> Bulk Smush” page and enable the “Optimize original images” option there. You will need to bulk-smush images again after enabling it but it will process those original images then.
Note: When “Optimize original images” option is enabled, I would also strongly recommend enabling “Backup original images” option as well; it will increase use of storage space on server but it will let you easily restore those original images in case e.g. their quality would drop too much due to compression.
Kind regards,
Adam
