Since you do not use Photon, the carousel, or Tiled Galleries, Jetpack should not impact the way images are displayed on your site.
Everything seems find at the moment; have you disabled BJ Lazy Load?
I also noticed that your theme includes an old version of jQuery, instead of using the version that comes bundled with WordPress.
It can create multiple conflicts with WordPress and with other plugins like Jetpack. You can read more about it here:
You'll want to look for the function loading jQuery in your theme's header.php file, or in the functions.php file. Once you find that function, you can remove it and enqueue the proper version of jQuery as explained here:
If you do not feel comfortable editing PHP files, you can also contact the theme author and ask them to solve the issue.