The actual Image Size is 2MB. This was enough for Full Screenshot on the MacBook Air.
But for the MacBook Pro 13" with the Retina Screen this is toooo small. For bigger screen it must be much worse too.
Please allow an Image size which goes on with the newest technology without using a compressor.
I always use the Command-4 screenshot. So I can show what I want in the image. But this creates images size files of 2,5MB. So the 2MB is too small.