Setting size of "square"

I’m really glad to see that someone decided to continue develop the old plugin, which I’ve been using so far, and making it responsive!

However, I’m really missing the old custom alternative when setting the size of the photos. Can I edit the code to source the 150px square from Flickr, instead of the 75px one?

Thanks in advance!

https://www.ads-software.com/plugins/responsive-flickr-gallery/