I would recommend you upgrade K2 first (looks like a really old version).

Secondly, you should have a look at SIGPro: www.joomlaworks.net/extensions/commercial/simple-image-gallery-pro

There's a reason it's the top commercial image gallery for Joomla ;)

The subscription provides you access to updates and support through our helpdesk system. It does not limit the extension's functionality. In other words, it will work even if you don't update your subscription. However if there is a breaking change in Joomla or e.g. Joomla 4 is launched AFTER the end of your subscription, you won't have access to the newer version unless you subscribe again for 6 or 12 months. And unlike other Joomla extension developers, we don't limit usage per domain, you're free to use your copy in as many sites as you want.