Photos on your listing pages load slowly, and the gallery is sluggish when you scroll through it.
Why this happens. HomeRunner sites use the HomeRunner Image Optimizer plugin to serve resized copies of your photos, sized for the page. When that plugin is inactive, the gallery loads the full-size original photos straight from your PMS image storage instead. Each original can be several hundred KB, and a page can have dozens of them.
What you can do. Contact HomeRunner support and ask them to confirm the Image Optimizer is active on your site. Once it is, the same photos arrive at roughly a seventh of the original file size and the gallery scrolls normally.