Hey Evegenii,
This will unfortunately rely on where these thumbnails are called in your theme for display.
Wherever they’re displayed, the process here would be to first use the WordPress function add_image_size() to register a custom thumbnail image size of 360 x 200. Then, specify this size in the place where the thumbnails are being called in your theme.
Finally, if you import images and they’re too large, you can use the awesome “Regenerate Thumbnails” plugin to just quickly make a down-sized version of the thumbnails after you import events → https://wordpress.org/plugins/regenerate-thumbnails/
Cheers,
George