There is an area above the avatar in the Forum Profile section with some information regarding that page. If a line about avatar size could be added it would be helpful. Or perhaps when an avatar is denied due to size a reminder of 150x200 could be included in the error message. I know there are several places avatar size is mentioned in various posts, however, for the ones who may change their avatar only once a year or so the search for that information can be frustrating.