Gal and I were chatting about this via email, and I much like his suggestion on the usability side of things. Trying to change multiple quality settings was very tedious and cumbersome.

As to the validity of using quality 100, I would first like to point out that WP decreased the quality (from 90 to 82 several years ago), because they found additional savings (and thus speed) could be had without affecting the user experience (based on real user tests). Deviating from that is not a great idea, but what are the consequences if you do?

To find out, I ran a small set of tests (on six images). Changing the quality level from 82 to 100 resulted in over 600% increase in file sizes. That is a huge difference in page speed, and can create a really poor experience for end-users, causing the site owner to lose out on sales, traffic, and everything that really matters to them.

Now, we did one additional test, which was to compare those image after processing by a plugin like EWWW Image Optimizer, using our Premium compression. The difference in size still averaged 23.5% after applying our industry-leading compression to the thumbnails. I certainly wouldn’t give up that much file-size just for a tiny bit more quality.

In previous tests, we’ve found you can go up to about quality 90 before you start seeing such dramatic (6x) size increases, but going above that gets out of control quickly. See also https://docs.ewww.io/article/12-jpg-quality-and-wordpress

• This reply was modified 2 months ago by nosilver4u.