There is already org-image-actual-width but the problem with that one is that images that have quite small width, but are tall will be scaled and become very tall.
I think it would make sense to introduce something like org-image-max-width, which would scale images that are larger than this width, but leave images within this width alone. Another interesting thing would be to be able to adjust the max-width to the width of the buffer, but not sure how well that will play in all cases and how complex that would be. Any thoughts on this? Best regards, Terje Larsen