Multiple images upload issue (Sizing)

We are trying to upload a gallery of images all at once and have them displayed full size in a single column. We create the gallery and then enter the code: [gallery columns="1" size="full"] as found in this post:https://en.forums.wordpress.com/topic/how-to-insert-multiple-images-at-once-not-with-gallery?replies=20

However when we do this the images only grow a bit on the vertical side and not on the horizontal. You can see the issue we are having on our blog here:

https://www.primalucestudio.com/blog/

Any advice on how to get them to all upload full size and display properly?

Thanks!