chromium/third_party/blink/web_tests/css3/filters/effect-blur.html

<style>
img {
    margin: 10px;
}
</style>
<img style="filter: blur(0)" src="resources/reference.png">
<img style="filter: blur(2px)" src="resources/reference.png">
<img style="filter: blur(3px)" src="resources/reference.png">
<img style="filter: blur(10px)" src="resources/reference.png">