background: background properties;

Shorthand, sets all different background properties.

background-repeat: no-repeat;

Values:
repeat-x  // repeated horizontally 
repeat-y  // repeated vertically 
no-repeat // not repeated 
repeat    // repeated throughout
space     // repeated with whitespace and nonclipped
round     // stretched as size increases

Sets how background images are repeated.

background-origin: border-box;

Values:
border-box  // positioned relative to border box
padding-box // positioned relative to padding box 
content-box // positioned relative to content box

Sets the backgrounds origin.

background-color: color value;

Set the color of a background.

background-position: top;
    
Values:
top left // top center // top right 
center left // 
right 
center 
x  y - offsets

Sets initial position of background images.

background-clip: border-box;

Values:
border-box  // extends to outside edge of border
padding-box // extends to padding edge
content-box // clipped to content box

Use image for text
background-clip: text;
-webkit-background-clip: text;
color: transparent;

Set the color of a background.

background-image: url();
background-image: linear-gradient();

Set an image as a background.

background-size: contain;

Values:
contain // large as possible without stretching or cropping  
cover   // fills the container
unit unit  // use px or rem set width and height 

To change the size of a background image.