As simple as it is ... !!
change this start picture that appears always when operate your MacBook , from the default picture
to any picture you like .. put be aware not to use prohibited ones according to Islam ..
for me I tried this ... with changing the background color ...
then I used this instead ..
just install the light application in your MacBook, then drop the picture in the square..
if you wish to change the background color, go to it under the image square ..
enjoy your MacBook Now !