Hi Leon,
Preload should wait to render the page until the preloaded images have been loaded from the network. So if you're on Page 9, and you go to the next page, if it's quick enough, it will load automatically. If it takes more than a few milliseconds, you'll see a loader while any preloading images for Page 10 are being loaded across the network, and then Page 10 will be shown once they're all ready. There might be some processing time for your broswer to render the image on top of other images.
Here's what I would do:
- Make sure you're on a recent version of SmartBuilder before you publish. 5.1+ had some improvements around this.
- Send us your example URL if you can, and/or a couple pages from your source file. We'll check it out - there might be other things causing the issue than network delay. Let us know when/where you've see the problem, as well as what OS and browser you were using.
- For trying to reproduce the issue, when you load your sample, you can have the Network panel open and there's usually an option to Disable Cache, which simulates a first time viewing every time. Attached image is Chrome's Network panel.