You can import a simple logo file to display on your website, or a banner image file (JPG or GIF) with a logo and imagery.
Click on the Content menu option; Click on information; Select the link you're working with; click Edit; under the existing picture, should be a remove option; click save after you remove the picture.
To upload a picture follow the prompts to upload a the file and be sure to click Save.
The ideal logo size is approximately 250-300 pixels wide.
The ideal size for a banner is approximately 600 pixels wide.
Crop the logo or banner so that there is minimal blank white space on all four sides.