Simple Image Gallery Pro v3.5.0 is now available to download or upgrade. New gallery layouts (templates) have been added, all popup engines have been updated and there are many compatibility improvements (compared to v3.1.0) with Joomla 3.8.8+, K2 2.9.0+ and PHP versions up to 7.2.
Frontpage Slideshow v3.11 is released today addressing an issue related to image selection with K2 items as slide source.
You know what they say about good wine - it takes time to mature. Although we've been providing responsive layouts through our helpdesk system to customers for some time now, it took a little longer for us to decide andbundle them with the default slideshow templates as in most cases, customers were creating their own unique (& responsive) styles, exactly because Frontpage Slideshow is probably one of the easiest slideshow systems to style (pure CSS goodness).
It's highly recommended that you update Simple Image Gallery to v3.6.0.