Wikimedia Commons Picture of The Day for WP Login

The Media Focus Point Plugin ensures the key area of an image or video stays visible, regardless of resizing or layout changes.

XO Post Background is a plugin to set background image and color for each post.

Configure WordPress updates settings through UI (User Interface).

Allow users to change the website style while reading at night, enabling them to easily read and spend more time on your site.

Background Per Page allows you to set a custom background per page (or post) as well as set up a default background for all other pages/posts.

For themes with background images, creates a parallax effect when scrolling. Super simple; no configuration. Just works.