Note: The Brand Kits feature is only available on the Premium Plus subscription.
There are no particular image requirements for the image you upload as a brand logo.
There is no limit on the size of the image you want to upload. However, depending on your internet connection, if uploading an image takes too long, your upload may timeout.
All typical image formats are compatible with brand logos, including .jpg, .png, and .jpeg formats.
Read this helpful guide to learn more about customizing Brand Kits.
Check out this video to learn how to create your brand logo: