Even a large entity such as the U.S. Postal Service can have graphics that are sub-optimal. Compare the difference for how the logo appears as of July 1/2016, relative to how it should look:
Why does it look blurry? The logo is a fixed dimension PNG file, but it’s later scaled via HTML. Don’t do this.
Always have your image present as 1:1 to the user whenever possible, especially on corporate branding.
Even worse, they only scaled it by 3 pixels horizontally and 1 pixel vertically. Just makes no sense.