How to display logo

http://wpdemo.in/testingtedst/

Is it possible to have a jpg/png logo at the top instead of the html text title?
I have tried putting in the url in the branding-"Insert your logo full url here" section but it does not display it. Under the site title if I delete everything it shows "Business Services" so I found myself putting some blank spaces in to get rid of the text.

I know this is going to be really obvious once its pointed out to me but I am still scratching my head at the moment so I thought Id ask for a nudge in the right direction.

Kind regards
Mark