The Responsive Image Gallery template keeps all of your thumbnails the same size. You can adjust the dimensions for the thumbnails. Once you open the gallery, the lightbox will adjust automatically to the size of the image and the size of the screen.
This is the default template for FooGallery. However, if you have changed your gallery defaults, you can select this template from the drop down templates menu above the Gallery Settings.
Below is a screenshot of the gallery preview for the Responsive Image Gallery.
The general settings for the Responsive Image Gallery allow you to adjust the size of your thumbnails. You are also able to link the images to a lightbox, and select the lightbox you want to use. Additional settings let you change the spacing between the thumbnails and set the alignment of your thumbs.
Here’s a quick overview: