The image is a 9 MB 5120x2880 JPG. Same size for the day one. Forum settings prevent posting an image of that size. If you wait long enough, I'm sure somebody will post it on one of the several image sharing sites out there. Then, Apple will probably make a DMCA claim to have it taken down at least until the public beta is out later in the month (or they just might not even care, and leave it out there.)
FWIW, there's also a dynamic HEIC format one that's 114.5 MB in size. Changes depending on local time of day.