Maximum size of logo in Scholar

What is the maximum size of the logo that can be uploaded in Theme Options -> Header settings:

Do you to use a custom large image logo rather than domain name text?
*Enter your url in the next section if saying yes

Insert your logo full url here
*you can upload your logo in media panel and copy paste the url here

Do you to use a custom square image logo and your domain name text?
*Enter your url in the next section if saying yes

Insert your square logo full url here
*you can upload your logo in media panel and copy paste the url here