@abisbee: To center align the image captions selectively
Go to => Appearance => Customize => Additional CSS and add the following CSS Code.
#attachment_5562 .wp-caption-text {
text-align:center;
}
This will center align the caption of the first image on this https://wellnesswarriorsboston.org/special-events/
Like wise if you want to center align the caption of only the second image use the following CSS Code.
#attachment_5565 .wp-caption-text {
text-align:center;
}
So, different images have different #attachment_ids. You will need to use the ids to selectively center align the captions.
Hope this helps you out. Have a good day! 🙂
Kind Regards,
Skandha