@elliottbnewcombjr and all, this time it worked. Not sure why but Elliott's instructions were good..
After copying the image I clicked on the 6th icon/Image, then clicked Edit and Paste. Width showed 2048 and Height 1536. So I again entered 600 in Width and this time 450 appeared in Height. All this successfully posted the image I've been attempting. So many thanks at last, even while not a sharp image.

