In order to change your login screen, follow these steps:
you can use your favorite text editor to open this file. The file will open as follows through the gedit command:
Search for the term ‘lockDialog’ by pressing Ctrl+D and entering this keyword in the search bar. This way you will be directed to the location where we want to make the required changes. This is the section of the file we will be editing:
You need to replace the above-mentioned lines with the following ones:
background: #2c001e url(file:///[fileLocation/filename.png]);
Replace the [fileLocation/filename.png] part with the location and filename of the image you want to use as the new background.
You can see how our CSS file looks after we have made the changes:
Save this file by clicking the Save button located at the top right corner of the text editor.
Restart your computer for these changes to take effect.
Now when you log in to your system, you will be able to see the newly set up background instead of the default Ubuntu login image.