I, too, fail to see the need for a new consensus. You had one: the old gallery size. Upon what "consensus" was that changed? If it was reduced without the consensus of the community, why is one needed in order to restore it?

Why isn't this just a matter of changing a site configuration setting somewhere? Is there a technical limitation on the image dimensions (not file size)? As a web developer, I don't understand why there would be. The image dimensions matter not one whit for what it takes to store the images on the back-end (except indirectly), but you had a file size limit before. Why can't you use the old file size limit with the old image size limit?