This CSS code is defining styles for images. Let's break it down: 1. The `img` selector is targeting all `` elements in the HTML document. 2. The `transition` property is being applied to images with a duration of 100 milliseconds (`100ms`). The property being transitioned is `transform`, which means that any changes in the `transform` property will be animated over the specified duration with an ease-in-out timing function. 3. The `img:hover` selector is targeting images when they are being hovered over by the mouse cursor. 4. Inside the `img:hover` rule, the `transform` property is set to `scale(1.1)`. This means that when the image is hovered over, it will be scaled up by 10% (1.1 times its original size) compared to its original size due to the `scale` transformation. Overall, this code will create a smooth visual effect where images will scale up by 10% when hovered over, with a smooth animation transition of 100 milliseconds.