GRAV - gantry5 : change logo and modify height

Hi all.
I'm using "OER content space" skeleton and I need to change the original gantry logo with mine, changing original width and height. It's a jpg banner that I try to insert in various way without success.
Anybody had success on this ?

I cannot find a way to change logo height in order to fit with my banner so I edit the layout and:

• disabled top "logo" and "header" section
• create a new "custom html" section below
• put the banner using html (result as in talentdevice.com)