Gallery seems slightly off-centre

I have a centralised pic and text on my post and also a gallery but it seems slightly off-centre as if it’s aligned to the left. I tried the 2015 default theme plus a few others and the problem seems the same on all of them although not always as noticeable.

Here is an example of where it’s noticeable

https://574.b49.myftpupload.com/2015/10/the-younger-generation-we-rap-more-mellow-2.html

https://www.ads-software.com/plugins/easy-image-gallery/