The CSS background-size property sets the size of the background image of the element. Images can be left to full size, stretched or limited to fit the available space.

background-image: url('some-example-image.jpg');

Cover

background-size: cover;

Size in pixels or percentage

background-size: 300px;

background-size: 15%;

Contain

background-size: contain;

Background-Repeat

If the container is larger than the image, this will mosaic the image if the background-repeat property is not set to no-repeat.

background-repeat: no-repeat;

Background-Position

The background-position CSS property sets the initial position for each background image.

background-position: center;

Background-Color

Spaces not covered by the background image are filled with the background-color property, and the background color will be visible on background images that have transparency.

background-color: lightgreen;