[gnome-backgrounds] README: update for new world

[Jakub Steiner <jimmac src gnome org>]

commit 9948d49c285c90619939aa57f9e5eabf94603dd1
Author: Jakub Steiner <jimmac gmail com>
Date:   Tue Feb 8 14:07:49 2022 +0100

    README: update for new world
    
    - light/dark reality of post GNOME 42

 README.md | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)
---
diff --git a/README.md b/README.md
index b2d97e5..87575c7 100644
--- a/README.md
+++ b/README.md
@@ -8,11 +8,11 @@ This module contains a set of backgrounds packaged with the GNOME desktop.
 
 ### Default
 
-The default wallpaper has historically been strictly abstract, low contrast and provided in three daytime 
variants. The geometric pattern has oscillated around stripes and triangles and over the years has become 
part of the GNOME brand. Steering too much away from it will dillute the brand.
+The default wallpaper has historically been strictly abstract, low contrast. The geometric pattern has 
oscillated around stripes and triangles and over the years has become part of the GNOME brand. Steering too 
much away from it will dilute the brand. 
 
 ### Supplemental
 
-It is desirable to have a wide mix of themes and colors for the additional wallpapers. Photographs and 
illustrations that would otherwise be too contrasty and with high frequency detail to be a good backdrop are 
perfectly suitable. Photos should generally be at least 3840x2160px, with no artifacts such as chromatic 
aberation. Generally 16:9 aspect ratio is preferred as the wallpapers get scaled with the `background-size: 
cover` equivalent method and wide displays are becoming more and more common.
+It is desirable to have a wide mix of themes and colors for the additional wallpapers. Photographs and 
illustrations that would otherwise be too contrasty and with high frequency detail to be a good backdrop are 
perfectly suitable. Starting GNOME 42 each wallpaper shoulc come in two variants, light and dark. While the 
actual difference isn't well defined, the dark variant should try to limit the overall brightness.
 
 #### Cultural Considerations
 
@@ -22,17 +22,13 @@ GNOME is deployed globally. Be aware of some bad connotations in certain geograp
 
 ##### Resolution
 
-It is recommended to submit wallpapers of 4megapixels and above. This isn't a hard requirement for sharp 
noiseless cases (see below), but a good rule of thumb.
-
-##### Aspect Ratio
-
-Specific aspect ratio isn't mandated, all wallpapers are scaled 'to cover' in CSS terms (cropped to fit 
display). Do take various possible display aspect ratios into consideration when submitting wallpapers with 
strong reliance on composition.
+It is recommended to submit wallpapers of 4megapixels and above. Photos should generally come in the 
standard size of 4096x2160px, with no artifacts such as chromatic aberration. The wallpapers get scaled with 
the `background-size: cover` equivalent method but due to portrait aspect for displays being rather rare and 
the texture size being a real constraint we have not switched to square backgrounds yet. Do take various 
possible display aspect ratios into consideration when submitting wallpapers with strong reliance on 
composition. Important elements might get cropped.
 
 ##### File size
 
 Unfortunately due to distribution limits, the background collection has to keep its size contrained to 
around 40MB. This forces us to replace assets rather than add them. You can download the 
[Nostalgia](https://flathub.org/apps/details/im.bernard.Nostalgia) app to view previous release wallpapers.
 
-One wallpaper is reserved for plain color to be used for remote access where it's benefitial for the 
compression algorith to cope with it with ease. 
+One wallpaper is reserved for plain color to be used for remote access where it's beneficial for the 
compression algorithm to cope with it with ease. 
 
 ##### Sharpness