Anil Sardemann

This plugin distinguishes between block and non block themes to add a fullscreen background image to WordPress. It is set either to the body tag (in case of a non block theme) or to the wp-site-blocks class (in case of a block theme). Upload an image or choose one from your media library. Simple plugin that allows you to set a background image for your website easily.
<a href="https://playground.wordpress.net/?plugin=custom-background-image" title="WordPress Playground Demo" rel="nofollow ugc">Demo</a>

Custom Background Image

Simple plugin that allows you to set a background image easily. Upload an image or choose one from your media library.

WordPress.org

Nick Halsey

This plugin is a WordPress core feature-plugin that adds cropping to background images for parity with header images. For this particular feature the implementation is quite simple, but it’s starting out as a plugin to gauge user interest in this feature and whether the feature improves the user experience of background images.
This plugin requires WordPress 4.3 Beta 3 or later.
If you’re interested in contributing to this project, ping @celloexpressions on <a href="https://chat.wordpress.org/" rel="nofollow ugc">WordPress core Slack</a>. Please comment on the trac ticket with ideas and feedback: https://core.trac.wordpress.org/ticket/32403.

Background Image Cropper

Easy too use and i hope to see this plugin have an editor image while cropping images.
Thanks

Hope to see more option with editor

This plugin is a WordPress core feature-plugin that adds cropping to background images for parity with header images. For this particular feature the  …

Custom Background Image vs Background Image Cropper