Twenty Thirteen Image Gallery Issue

Hello,

I’m having an issue with the native image gallery that comes with the Twenty Thirteen theme. I just created a couple of posts in my website’s blog, one with simple images and another one with a gallery of images. Once you click on the gallery, it’s oddly big, the control arrows take you to other images that are not in the post. Once you click the other post with images only, the images get so big. It looks something is not right, it doesn’t look like the preview theme I’ve seen. I tried to deactivate all plugins, but nothing. Just so you know, I created a child theme with very few small css changes, but nothing major as you can see in my page, I wanted to keep it simple. Here is the link:

aldocherres.com/blog

Any help would be greatly appreciated, thanks!

Aldo