Picture Captions Alignment

Hello. I was wondering if there is a way to change the alignment of captions under photos? Regardless of how the picture itself is aligned, the captions always alright to the left. I would like to be able to center the captions.

The second pictures in both of my most recent two posts show the issue: https://bewareofsloth.wordpress.com/

I’m very new to WordPress, so my knowledge is minimal.