Insert image dialog, entering 'n%' distorts the image

[Joel]

Duplicate by trying to insert an image, then setting the width to 100%. It immediately distorts the image proportions. Lock ratio on or off makes no difference. If I try to fix it by removing the height, the Preview displays the image with it's original height, instead of empty as expected (see attached screenshot).

If '%' is input it could simply clear the height completely and let the browser do the scaling of the image in the preview box. Then the user can input a custom height % if they so wish to do. If I try to remove the preview image height CSS rule in Inspector the image scales beautifully so I'd think that easy fix would work.

Replicated in IE 9 and Chrome 26.

[Joel]

Shows how the image input dialog width/height is incorrect