making image smaller png css code example

Example 1: make an image smaller css

css:
.example-class {
    width: 400px;
    height: auto;
}

html:
<img class="example-class" src="example.jpg"/>

Example 2: how to make png smaller css

.pdflink:after {
    background-image: url('/images/pdf.png');
    background-size: 10px 20px;
    display: inline-block;
    width: 10px; 
    height: 20px;
    content:"";
}