The use of background images on WordPress sites has become more and more popular recently.
To upload image follow the next steps:
Download the plugin here and save to your local computer.
Install Plugin
From the left-hand navigation menu in WordPress:
Go to Plugins>Add New:
Click on Upload:
Click Choose File, find the zip file, and then click Install Now:
Click Activate Plugin:
Apply a Full-Screen Background Image
Once the plugin has been activated:
Go to Appearance > Fullscreen BG Image:
Click Choose Image.
Either upload an image from your computer or choose one from the WordPress Media Library:
Click Insert into post.
Once the image is uploaded, you will see a confirmation screen, allowing a preview of the image.
Click Save Options:
You will now see the image you chose to use for the background when you view your site.