We are only a few weeks (days?) away from Apple releasing MacOS Big Sur but if you want to get your hands on the Dynamic Wallpapers for the release, you can do so right here on Average Apple Guy.
There are two of these day-to-night wallpapers available. First is the marketing splash that you’ve seen as well as a photo of Big Sur. Both are .HEIC files and will work on macOS Mojave and later. Given the size of these files – 40+ MB each – I’ve created a link on Google Drive for you to visit and download the .HEIC files.
To use these wallpapers, the best and most straightforward way to do so is to create a folder on your Mac or in iCloud to store them. Then, using the Desktop & Screensaver settings, you can add that folder to the listing and select the one you want to use. In my screenshot below, I’ve named the folder Big Sur and then added it to my list.
Obviously in order to get the true impact of these wallpapers, you’ll need to have automatic Dark Mode enabled. You can, of course, select Light or Dark and get either the light or dark wallpaper as your desktop.
Finally, if you just want the static marketing wallpaper, the image is below and you can right-click and download it to your Mac (or PC).