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Most of this comment is just you being dismissive about an idea without any real reason presented for being dismissive. The only useful bit here is actually in

Most of this comment is just you being dismissive about an idea without any real reason presented for being dismissive. The only useful bit here is actually in your linked comment which most people will probably not see and that is that lazy loaded images tend to fail a lot on poor internet connections. I would argue that even in that case, lazy loading images arent necessarily bad depending on the situation: imagine a site like imgur, where you will likely browse to another page without ever loading all of the images. In that case, the browser would still have loaded the image if it were an img tag and this way you get to the next page faster. Sometimes the browser will cancel the img download, but its not reliable. If the js were coded to handle errors on loading the image, that would probably be a better situation overall.

chrismorgan 8y ago
It’s much worse than just the potential for failure, as I indicate in other places I’ve written about it. If I ever see evidence that scroll-based lazy loading has occurred, it has failed in its mission: it didn’t load the image in time. And in practice, this happens a lot of the time, especially in higher latency situations. You can’t sufficiently-well predict what the user is going to do and so only load it just in time. It doesn’t work. I am inspired by your grumbling to write a blog post entitled “Scroll-based lazy loading of images is always bad”. I won’t publish it for a while so I can treat the subject methodically (and I’m busy for the rest of today), but it will come. Thanks for the imgur comparison; the wording I’ve used does fall down there; in my mind I had distinguished scroll-based lazy loading and scroll-based lazy loading of images. When talking about scroll-based lazy loading of images, I meant where you have content that contains images, rather than situations where the images are the content. (That is, I’m talking about lazy loading just the <img>, not lazy loading content in general.) There are definitely applications for which loading everything up-front is impossible (e.g. imgur infinite scrolling on mobile) or impractical (e.g. showing all the 10,000 messages in a mailbox in an email client that deliberately eschews pagination, like FastMail); in such situations, lazy loading is necessary and while it will often be annoying and imperfect there is and can be no better solution. Where images are embedded in the content, however, I think that my position is still reasonable; there is an alternative: just load eagerly rather than lazily. Now articles and blog posts are the primary application I have in mind, and I can’t think of any other applications where my position would not hold—given the caveats of interpretation specified in the previous paragraph—but I’m willing to hear other suggestions.

chrismorgan 8y ago

It’s much worse than just the potential for failure, as I indicate in other places I’ve written about it. If I ever see evidence that scroll-based lazy loading has occurred, it has failed in its mission: it didn’t load the image in time. And in practice, this happens a lot of the time, especially in higher latency situations. You can’t sufficiently-well predict what the user is going to do and so only load it just in time. It doesn’t work. I am inspired by your grumbling to write a blog post entitled “Scroll-based lazy loading of images is always bad”. I won’t publish it for a while so I can treat the subject methodically (and I’m busy for the rest of today), but it will come. Thanks for the imgur comparison; the wording I’ve used does fall down there; in my mind I had distinguished scroll-based lazy loading and scroll-based lazy loading of images. When talking about scroll-based lazy loading of images, I meant where you have content that contains images, rather than situations where the images are the content. (That is, I’m talking about lazy loading just the <img>, not lazy loading content in general.) There are definitely applications for which loading everything up-front is impossible (e.g. imgur infinite scrolling on mobile) or impractical (e.g. showing all the 10,000 messages in a mailbox in an email client that deliberately eschews pagination, like FastMail); in such situations, lazy loading is necessary and while it will often be annoying and imperfect there is and can be no better solution. Where images are embedded in the content, however, I think that my position is still reasonable; there is an alternative: just load eagerly rather than lazily. Now articles and blog posts are the primary application I have in mind, and I can’t think of any other applications where my position would not hold—given the caveats of interpretation specified in the previous paragraph—but I’m willing to hear other suggestions.