This CSS code defines a class called `resize-image` which is used to style an element with a background image. Here is an explanation of the code: 1. `background`: This property sets the background image for the element. In this case, the background image is `image_1.png` which is positioned at the top left corner of the element and it is set to not repeat. 2. `-moz-background-size`: This property is specific to Firefox browser (Mozilla). It sets the size of the background image to 200px in width and 300px in height. This property is used for the browser's compatibility with the background image size. 3. `-o-background-size`: This property is specific to Opera browser. It also sets the size of the background image to 200px in width and 300px in height. 4. `-webkit-background-size`: This property is specific to WebKit browsers (like Chrome and Safari). It sets the size of the background image to 200px in width and 300px in height. Overall, this CSS code sets a background image for an element with class `resize-image` and ensures that the image is displayed at a specific size for different browsers.