Topic: Gallery loading slow on mobile – tips to optimize?

I’ve been using Juicebox-Pro for a couple of years now and really enjoy how clean and customizable it is. I’ve set up several galleries for client portfolios (mostly photographers and designers), and things have been running smoothly—until recently.
I’ve noticed that on some mobile devices (especially older Android phones), the galleries load noticeably slower than expected. Images are optimized (under 300 KB on average), and I’m lazy-loading them using the built-in settings. Still, the initial load seems to lag a bit.Monkey Mart
A few questions for the experts here:

  1. Are there any less obvious settings I might be overlooking in Juicebox-Pro to boost mobile performance?

  2. Does the number of thumbnails per page or image scaling method significantly impact loading speed on phones?

  3. Is anyone using any kind of CDN or third-party hosting tweaks to boost image delivery within Juicebox?

Just trying to figure out if it’s my setup or just mobile hardware limitations.

Any insight or experience sharing would be appreciated!
Thanks in advance!

Re: Gallery loading slow on mobile – tips to optimize?

Perhaps the two most influential factors in the loading of a gallery are the speed of the web server (where the gallery files are hosted) and the user's internet connection. Unfortunately, there is little you can do about either of those.

You could maybe tweak the size of your images. From memory, if you allow JuiceboBuilder-Pro to resize your images at default settings (medium sized images at 1024 x 768), the resulting images tend to be around 120KB each. This is significantly smaller than your current average of 300KB and images should, therefore, load faster (and they should still hopefully be of a reasonable quality for web gallery use).
You could also take advantage of Juicebox-Pro's Multi-Size Image Support (see here for details) where the gallery stores different sizes of images and serves up smaller ones on mobile devices. It might make a difference (depending on factors such as the device's screen size and pixel density).

I don't think the imageScale mode will make a big difference to the loading speed but the imagePreloading value (Large Screen Mode only) might. (Both of these configuration options can be found in the Main Image Options section here). When setting the preloading to the default value of PAGE, Juicebox will preload all images on the current thumbnail page so reducing the number of thumbnails per page should speed up the initial load a bit. Alternatively, you could set the preloading to NEXT, whereby only the next image in the gallery is preloaded. This should provide the fastest possible loading time (less initial burden on the browser) but I can't say whether it will make a difference on your Android device. It's something you can experiment with, though.