Thank you for your "one line review". Looks like you a first user who had any complaints for a slow work of our gallery, btw. we have hundreds of the customers who creating really huge galleries with out any problems. Even more appreciated that you didn't get a chance to submit any support ticket, but find some time for 2 stars review.
To be honest looks like you really a not our customer, bec. if you would be, you should know that in our extensions implemented: Joomla! native caching support;
caching CSS and JS and as result using fully pre-generated files; images caching (it's generate during size definition process); function for loading only visible images (to make page loading time minimal); Implemented ajax based pagination function with partial pre-loading of the images;
Also we help to sort all kind of problems in our support section, in some cases even if the reason of the problem not our extensions at all.
So looks like "slows down my webpages" has some other reason.... or it's myth at all. Thank you again for your fairness. Good luck in your own business!