Compression of images

We like everyone else have been trying to get sites faster with Google Speed test over the last few months.
Why does Smush not compressed the images to the reduction Google wants. It appears to only slightly compressed the image and unless we drastically compressed the image first with a third party tool Google is not happy with the compression

Your thoughts please

  • Adam Czajczyk

    Hello Barry,

    I hope you're well today and thank you for your question!

    PageSpeed Insights reports suggested compression in two ways: either as "Compression" or as "Compression and resizing".

    As for the first one. We don't know what exact algorithms are used by Google (as they don't share it willingly with anybody) but WP Smush Pro by default is performing lossless compression that's based on removing only that data from an image that won't affect it's quality. That might be less efficient than Google expects. There's an optional "super-smush my images" option that provides much stronger compression and would give better results but please note that whether to use it or not - it depends on the images and the site; if a quality is not "critical" it would be a good choice as compression results would be much better and while the quality drop may occur it shouldn't be significant in most cases.

    The second way PageSpeed Insights report that is "Compression and resize" and that suggest that a "larger image is loaded into smaller holder". For example: an 800x600 pixels sized image is loaded into "div" element of a fixed size of 500x400 pixels. That would also cause Google to report that but requires either tweaking up the theme that's used or resizing images to fit containers. That's more of a design work though.

    That being said, we are constantly improving WP Smush Pro, including its algorithms so the way it optimizes images also improves. I believe that in future it will be able to optimize them even more.

    If you have any additional questions, let me know please.

    Best regards,

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