Gallery container size

Hey everyone!

I hope one of you can help me with an issue that has been making me pull my hair out…..

I want to post a gallery of 6 thumbnails next to each other. This is fine but the thumbnails are too small. There is a lot of white space that could go to good use, but I can’t figure out how to do this.

Resizing the thumbnails in the settings doesn’t seem to work, because I believe the container the gallery is in doesn’t allow it to resize over a certain limit. I could go into the code and fix it, but I wouldn’t know where to look.

I am using the ‘twenty fourteen’ theme and my website is: http://nolimits.almering.nl/?page_id=70

Greetins,
Andrea