I can resize (and make it 8-bit) of course and save as TIF with LZW compression, which would maybe yield a 10MB file. I just saved the whole thing as high quality jpg, which is nearing 4MB.
So, what would you like 8-bit small tif or full high quality jpg? The worked file (not much worked on) is nearing 4 too, so together they would be within 8MB.