I have not noticed this before, usually I will try to ensure images are compressed, and that they are Progressive.
Can anyone tell me how on a recent test, I manage an A score on images when 2 need compressing, and 5 are flagged as needing saved as progressive?
Compress images 90/100
Yet tests with better scores than above get a D score. Confused…
Also (related) Images recommended for compression e.g.
34kb compressed to 12kb saving approx 20kb What criteria does Webpagetest.org use to decide that is a reasonable value, are there any guidelines or info relating to this?