There is indeed a very definite resemblance between aunt and niece in said portraits. I think Amalia really had a longish face - typical of the Hapsburg's then -- but she had enough fat on her face to make it a bit round. I have stumbled into a Czech site months ago and the study on her remains said that she had a long face. But in her younger years, I guess it wasn't very apparent. I have seen portrait of Amalia by Rotari in her early teens and she had a quite a roundish rather than a longish face. I also think that weight loss, very apparent in her later years, emphasized the long face.