Pagespeed resized images low quality

mod_pagespeed should only resizes images if you have set explicit width and height attributes in your HTML and the resize_images filter is enabled. Is this image being resized to the wrong size for your site? Or do you have explicit width and height attributes, but still want the image at full size for some reason (ex: Retina display, zoom)?

You can turn this mod_pagespeed feature off with:

pagespeed DisableFilter resize_images;

Have to say I cannot see the diff in your 2 photos either.That said, I think the setting you're after is:

ModPagespeedImageRecompressionQuality -1

See: https://developers.google.com/speed/pagespeed/module/filter-image-optimize#recompressionquality

This keeps all the image_rewrite filters working, but enables lossless compression when recompressing images.

Well, you should just modify which filters are enabled. Look here: https://developers.google.com/speed/pagespeed/module/filter-image-optimize.

You're probably using pagespeed EnableFilters rewrite_images; to optimize the images. Don't. (If you're not, then I'll change my answer).

rewrite_images is an alias for inline_images,recompress_images,convert_png_to_jpeg,resize_images, so just enable the ones you need:

pagespeed EnableFilters inline_images,resize_images

If you're not using nginx, then just use the appropriate Apache syntax or the correct filters if you're using the Pagespeed cdn service.

I honestly don't see a difference on my screen (not using a retina display). So Google might not be serving the right image in that it isn't respecting the difference for retina.

Look here: http://code.tutsplus.com/tutorials/the-right-way-to-retinafy-your-websites--net-31793

Looking at how the PageSpeed service (the scoring one not the module / cdn) scores things helps explain the logic behind the module / cdn because the latter follows the evaluative logic of the former.

Fix Google PageSpeed's "Serve scaled images" for responsive layout

A quick jab via Twitter: https://twitter.com/hkfoster/status/303480645785624578

Basically: if the problem is with retina screens, then you should just turn off the resize_images filter.