I think like most good educational graphic design, the image must be elegant--in that it is simple & clean to display at smaller sizes (e.g. less than 100x100px) but convey the central core of the concept. I believe that significant thought should be invested in the graphic design.
I don't have the technical expertise to design the coding. I would need to go to a 2nd party who have designed the structure where I could upload my image and my criteria & associate myself/institution with the granting of that badge. That 2nd party would also have to help me keep track of those to whom I/my institution have granted the badge.
I'm pondering how much I would like to have some automated credentialing toward the badge in whole or part. Does automated credentialling devalue higher level learning? more complex learning?