Logo in Impreza not sharp

I’m a new user. I like what I do. But I now have something I don’t understand. The logo is not sharp. See www.pi-it.nl. How can I improve it?

Your logo image is too small and being stretched/increased which makes it look pixelated.

You wither need to adjust the CSS to make it the right size for the existing logo image or upload a bigger image

Charlie, THANK YOU, i’ve been experimenting and haven’t reached the final settings yet, but I’ll get there, thanks to you!