Unofficial documentation for the iCloud Apple device image URL format

gistfile1.txt

https://statici.icloud.com/fmipmobile/deviceImages-9.0/iPhone/iPhone9,4-2-3-0/online-infobox__3x.png
                                                   A   B      C         D E F G

A: deviceImages version seems to determine the format of the image specifier (C, D, E, F)
B: device marketing name
C: device model identifier
D: color cover glass (front color)
   1 - Black
   2 - White
E: device enclosure color (back color)
   1 - Space Gray
   2 - White
   3 - Gold
   4 - Rose Gold
   5 - Stainless steel white (Watch only)
   6 - Stainless steel black (Watch) / Product Red (iPhone)
   7 - Gold 2 (?) / Edition (Watch only) / White Ceramic (Watch only)
F: unknown
G: image variant
   online-sourcelist.png
   online-sourcelist__2x.png
   online-sourcelist__3x.png
   online-infobox.png
   online-infobox__2x.png
   online-infobox__3x.png
   
Examples:

White iPhone X
https://statici.icloud.com/fmipmobile/deviceImages-9.0/iPhone/iPhone10,6-1-2-0/online-infobox__3x.png

Black iPhone 8 Plus
https://statici.icloud.com/fmipmobile/deviceImages-9.0/iPhone/iPhone10,2-1-1-0/online-infobox__3x.png

Gold iPhone 8 Plus
https://statici.icloud.com/fmipmobile/deviceImages-9.0/iPhone/iPhone10,2-2-3-0/online-infobox__3x.png

Black HomePod
https://statici.icloud.com/fmipmobile/deviceImages-9.0/HomePod/AudioAccessory1,1-1-1-0/online-sourcelist__3x.png

White HomePod
https://statici.icloud.com/fmipmobile/deviceImages-9.0/HomePod/AudioAccessory1,1-2-2-0/online-sourcelist__3x.png

You may also be interested in the filename "online-nolocation_ipad__3x.png", I believe this is the highest resolution available so far.

...I'm also curious, I'm looking for the icons used in iOS/MacOS System Preferences, which still display my iPhone 12 mini with its default live wallpaper from launch, rather than the iOS 15 wallpaper. I'm curious if anyone has any clues where these files may be getting pulled from?

Edit: guessing settings is just a webview, because I can drag the icons out of it and they're just images/URL's (see: https://twitter.com/SkyVelleity/status/1500046892822319106 )

This is the file System Preferences was using:
https://appleid.cdn-apple.com/static/deviceImages-10.0/iPhone/iPhone13,1-3b3b3c-ccc7d7/online-infobox__2x.png
And we can go a bit bigger if we want:
https://appleid.cdn-apple.com/static/deviceImages-10.0/iPhone/iPhone13,1-3b3b3c-ccc7d7/online-nolocation_ipad__3x.png

I'm not sure if the hash here (3b3b3c-ccc7d7) includes the OS version or what, hence why this is displaying the original wallpaper, as I haven't updated this device past iOS 14.

As this is using deviceImages-10.0 looks like apple may now be including OS version too.
Not entirely sure if it's relevant but I suspect this may be the path needed to retrieve the hash:
libimobiledevice/libimobiledevice#818

These two it is just an RGB hash. #3B3B3C and #CCC7D7.