WordPress 5.5 Lazy Loading on Mobile

WordPress introduced “Lazy Loading*” of images a little more than half a year ago, in version 5.5. Previously, one had to use a plugin to get that feature and in fact, it was included in many caching and optimization plugins, as well as WordPress’s own “Jetpack” multi-functionality plugin.

When WordPress 5.5 was released I asked in the Jetpack support forum whether the Jetpack “Lazy Load” feature can be disabled now (wouldn’t want two features like that to interfere because who knows, it might break image loading altogether, or whatever else). That was confirmed, and so I went ahead and disabled Jetpack’s “Lazy Load” feature, in favor of the WordPress 5.5 built in functionality.

I didn’t bother to test it until recently, when I wrote about photo presentation online — to then find out that, while the WordPress Lazy Load works fine on desktop browsers, it doesn’t “lazy load” any images on mobile devices! I tested this with Safari and Firefox on an iPhone and the bigger galleries like my Color and Black & White portfolios were just awfully slow.

Since I have both a caching plugin with a Lazy Load option and Jetpack installed, I tried both of these Lazy Load features instead, and both of them work on mobile, as expected. In the end I went with Jetpack’s Lazy Load again, which seemed to look and work better.

I’m scratching my head why the native WordPress lazy loading of images isn’t working on mobile for me. I tried this both on my self-hosted photography site and this personal blog here, using galleries. The way it looks, it’s not working on either, so it can’t be my theme or some plugin interference.

In any case, if you rely on Lazy Load, then you might want to double check on mobile. For testing it might be useful to disable the WiFi on your phone and use cellular data instead (depending on the speed of your internet connection and WiFi of course — if it’s fast, you might not be able to see whether the lazy loading works or not).

Let me know what you find. Is WordPress 5.5+ Lazy Load working correctly on mobile for you?

UPDATE 2021-04-02: I asked about this in the “Fixing WordPress” forum: https://wordpress.org/support/topic/lazy-load-not-working-on-ios-ipados/ and the reason why the native Lazy Load doesn’t work on iPhone’s is that Safari doesn’t support this feature officially yet (it can be activated under “Experimental Features”) and that Firefox on iPhone ALSO uses the Safari rendering engine. Duh! Jetpack’s Lazy Load feature on the other had DOES work because it is not HTML based, but uses JavaScript, apparently.


*) “Lazy Loading” means that web browsers (that support the feature, and by now most if not all of them do) are instructed to only load those images that are actually visible. It’s a very simple method to speed up website loading times. If you have an article or gallery with 50 images in them, only the first few will load, and then the browser will “catch up” and load the remaining images later, as you scroll down.

7 thoughts on “WordPress 5.5 Lazy Loading on Mobile

  1. So you might remember I ran into conflicting Lazy Load issues with Jetpack and another plugin that resolved itself when turned off. Lazy Load does seem to work on my site via mobile from my own browsing. However, I have it turned off via Jetpack. My Gallery plugin does have Lazy Load enabled, and I don’t think I turned it off on WordPress itself. Who knows.

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  2. I ended up turning off Lazy Load via Jetpack for the reasons you wrote — even when it does work it adds too much spacing between images and stretches the post out.

    I’ve also had to disable lazy loading in other caching plugins for similar issues.

    Ray

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    1. Oh, really? Jetpack’s Lazy Load gave you problems? It’s the one that seems to work best for me. The LiteSpeed Cache plugin (my hoster is using LiteSpeed servers) has an option but the layout shifts while loading are just crazy because it adds the LL feature to EVERYTHING — including the logo! xD

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      1. Oh yeah, that too.

        BTW, I also turned off Jetpack’s image caching because the image quality had degraded substantially. Is this the same for you or does it take time to clear up or something of the sort?

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      2. I had the same problem with the image quality. I turned it off a long time ago, and also because their cache doesn’t age and there’s no way at all to flush it, other than with a support request. I publish to WP directly from Lightroom (my self hosted installation, not this personal blog) and with Photon enabled there’s no way to update an image…

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