Thanks for working this out!
This is what bugs me about IPS, trying to find out what should be basic information like this or for that matter the recommended header background image dimensions (that bizarrely in 2017, we admin's still can't upload from the front end unlike a calendar event cover image or profile image!), is often like extracting blood from a stone.
It should be in the guidance section or FAQ for heaven's sake! Companies for instance like Twitter do it for their recommended header image sizes, because they know users will benefit from getting it right, and their product looks better as a result.
I'm having a bad day, ignore me.
