The images in this directory are compressed with AVIF via https://squoosh.app.

For images that have text (e.g. the keyboard images), use the following settings:
- Max quality 20
- Effort 5

For all other images, use the following settings:
- Max quality 20
- Effort 10
Add documentation for compression settings with squoosh.app
Add documentation for compression settings with squoosh.app

When I optimized the images, I forgot to write down the settings
I used to compress these images. Therefore, add a README to write
these down for future reference.

R=17a2cbc4e33156874a9862b0f530521117e66a3d@chromium.org

Change-Id: Ic8fc0215d9fa31dd6fa5d4a38adbb35fbe70073e
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/2428893
Commit-Queue: Mathias Bynens <17a2cbc4e33156874a9862b0f530521117e66a3d@chromium.org>
Reviewed-by: Mathias Bynens <17a2cbc4e33156874a9862b0f530521117e66a3d@chromium.org>
Auto-Submit: Tim van der Lippe <dba8716ee7f8d16236046f74d2167cb94410f6ed@chromium.org>
