Retina compression

  • Hi @nevma

    Your plugin offers some excellent functionality. I saw in one of your other retina support threads how you mentioned you personally would still prefer to have HiDPI support disabled so as to provide users with better speed. And I agree that speed is very important, particularly on mobile.

    I’m quite tempted to use the Adaptive Images plugin on a highly customized site where srcset has been poorly used as its excellent in that scenario. My only problem is trying to also support retina and do so without significantly impacting page speeds.

    But I don’t think that retina images (at least 2x ones) actually need to have massively bigger file sizes than non-retina ones. This being mostly because you can be a LOT more aggressive with image compression with images for retina displays than you can for non-retina displays.

    Just as an example using a specific image:

    For non-retina:
    480×296 quality:60 = 40.16K

    For 2x retina:
    960×592 quality:19 = 47.26K
    or
    960×592 quality:10 = 43.9K
    or
    960×592 quality:0 = 32.38K

    When doing it manually we have sometimes gone down to as low as 0 quality with an excellent end result, but I would say ~19 is a pretty safe average quality for 2x retina images. Bit more on this here: https://alidark.com/responsive-retina-image-mobile/

    I think if adaptive images was able to offer different compression settings for retina and non-retina and create and serve different files based on those then your HiDPI support setting would make a lot more sense?

Viewing 3 replies - 1 through 3 (of 3 total)
  • Plugin Author Takis Bouyouris

    (@nevma)

    Hello, @gnuworld,

    This is all very interesting, thank you very much for bringing this up!

    Well, one issue is that the image compression utility we are using right now is the one readily available by PHP, that is the PHP GD image library. Unfortunately, it is one that cannot get too aggressive without much compromising quality and it does not provide all the intricate optimization settings that an application like Photoshop or an online image optimization service do. There is no “save for web” here!

    Then again, the plugin is specifically designed to not be dependent on external tools or services! However, combining the plugin with such an external tool or service could be an option, perhaps as a new feature in the future or even as a pro feature.

    Also, having a different JPEG quality setting for HiDPI (retina) devices could also indeed be a possible new feature in the future. I am not too keen about it at first glance, because it would double the amount of generated images in the cache. Also the size of the images produced is not actually double, it is less, well, depending on the image and its colors, of course. But it could be a solution.

    Cheers,
    Takis

    Thread Starter Jonas

    (@gnuworld)

    Hi @nevma

    Yes, personally I’d be happy to pay for a Pro version with improved compression and HiDPI support.

    I get what you’re saying about being wary about doubling the cache. But since one wouldn’t want to compress non-retina images as aggressively as retina ones so as to not end up with artefacting in the non-retina images I would think that would be necessary for this kind of solution.

    Also only an issue for users for whom disk space is in short supply. I guess I’d feel it’s always good to have options – i.e. the ability to choose to have

    – fast load times, minimal loss of disk space but

      no retina support

    or
    – retina support, minimal loss of disk space but

      slower load times

    or
    – retina support, fast load times but a

      bigger loss in disk space

    Like the ‘fast, cheap, high quality’ scenario…can only ever choose 2 ??

    Anyhow, thanks for the feedback, I’m going to keep having a look around to see how else this challenge is being approached, but will keep an eye on where to you take this plugin.

    Keep up the great work.

    Cheers,
    Jonas

    Plugin Author Takis Bouyouris

    (@nevma)

    Thank you for the conversation and the nice ideas, Jonas.

    It’s all very interesting indeed and I would love to hear any additional feedback!

    Cheers,
    Takis

Viewing 3 replies - 1 through 3 (of 3 total)
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