Updated: Aug 17, 2019
On Tableau Server there are 2 Tableau logos.
1. On browser window - This logo cannot be replaced
2. The header logo -This logo can be changed using tab admin command (customize header_logo)
For header logo
Supported Formats: GIF, JPEG, or PNG.
Supported Size: Minimum 32 by 32 pixels and up to 160 by 160 pixels (larger files will be clipped)
To Customize the logo
Open command prompt as an administrator and type the following command
tab admin customize header_logo "<Location>\logo.png"