Change background of the login to the macOS of the Sierra, Yosemite and El Capitan
Change the background of the login to the macOS of the Sierra, Yosemite and El Capitan, to the largest, is a no-brainer: just set the desired background image as the background of the desk! However... there is a but: if we use the auto-rotate backgrounds, macOS/OS X does not follow our preferences and set as a background screen to login the system default.
With a trick, however, it is possible to ensure that this does not happen and use a custom background by using the auto rotation! The below guide applies to the operating systems macOS Sierra, OS X Yosemite and El Capitan.
As already mentioned, macOS sets the background of the login screen identical to that of the desktop, only with blur; instead, if we set the rotation of the backgrounds, the macOS will automatically use the default background of your system. Let's see how to change the wallpaper of the login to the macOS Sierra while maintaining the rotation of backgrounds.
Let's make sure that, if we use more desks, find us on the left. To change the wallpaper of the login to the macOS we set the first as a desktop background image that we want to use as the background of the login; we proceed with the classical procedure right click on desktop > Change desktop background removing if present uncheck “change picture“.
The fact that (even without closing the settings window) open the Finder and go to go > Go to folder. Write in the appropriate field in the address /Library/Caches and click on Go.
Inside it dovebbe appear in a file by the name com.desktop.admin.png; if not, wait a few minutes for this to be created. In the file there should be the image that we have chosen to which has been applied a blur effect.
At this point we can safely reset the auto-rotation of the wallpapers and then restart the Mac, we will see our background changed!
If you want we can also eliminate the blur effect with a trick, and without tinkering with graphics programs! To do so, we open with a Preview of the image that we want to set as login screen background, select all by pressing Command+A (or Edit > Select all) and copy it by pressing Command+C (or Edit > Copy).
Let us go back to the /Library/Caches and copy the file com.desktop.admin.png on the desktop, by dragging it. We leave open the finder, because we will need it shortly. Open the newly copied file in Preview and paste the image you copied previously on it with the key combination Command+V (or Edit > Paste).
NOTE: we may need to resize and move the pasted image to fit the dimensions of what will be the background.
Once you have changed the image, we save (Command+S or File > Save), take the file you just edited (the one on the desktop) and trasciniamolo again in /Library/Caches in the Finder opened earlier. We confirm that we will replace the file, and... voila, our new background is served!
Of course, if we have skill with programs of graphic editing, instead of using the game copy-paste-move, we can safely create the background that we want to use as your login to the macOS; the requirements that the image must have are the following:
The article Change background of the login to the macOS of the Sierra, Yosemite and El Capitan appears for the first time on ChimeraRevo - The best face of technology.