In the list on the left, select the legal entity for which you want to update the banner or logo. If it is already selected,
click edit and select banner from Dashboard company image type
Tip: The ideal resolution for a banner image is 1920 x 281 pixels. The ideal width for a logo image is 350 pixels.
Blog Syndicated with noreply@blogger.com (Mahmoud Hakim)’s Permission How to Add custom dashboard banner in dynamics 365?