My personal experience, and thus for proposing this is that, as a newer editor, I edited ~30 articles using the visual editor before I realized that this was happening. It seems like a straight-forward upgrade to the visual editor. By the way, I went back and modified those 30 edited articles using "upright". I have since noticed many articles with specific "px" instead of upright and manually fix those myself; so this seems to be a fairly widespread problem. So, when using the visual editor and dragging on an image to change its size, the underlying code should be in "upright" units rather than "px" units.

My personal experience is that, as a newer editor, I edited ~30 articles using the visual editor before I realized that this was happening. It seems like a straight-forward upgrade to the visual editor. By the way, I went back and modified those 30 edited articles using "upright". I have since noticed many articles with specific "px" instead of upright and manually fix those myself; so this seems to be a fairly widespread problem.